Roof Mounted HRU Systems

Outdoor air enters through an intake with the specified weather hood, louvers, bird screen and damper. These components help manage rain, debris and airflow. Intake temperature and humidity establish the incoming treatment load and inform recovery, bypass and frost-protection decisions.

Designated extract air is collected from the building and directed toward the recovery section. Its temperature, humidity, flow and operating schedule determine the available energy. The exhaust must be compatible with the recovery technology; recirculated return air is not automatically available for exhaust-air recovery.

Fresh-air filtration addresses outdoor particles, while exhaust-air filtration helps protect the recovery components from suitable extract-side contaminants. Filter classification and resistance depend on the application. Both clean and loaded-filter conditions should be included when selecting the fans and maintenance alerts.

The recovery section exchanges temperature energy between incoming and outgoing streams. Suitable membranes or wheel media may also transfer water vapour. When conditions favour recovery, the incoming air requires less downstream heating or cooling; the actual benefit depends on both streams' conditions and the exchanger design.

The supply fan moves preconditioned outdoor air into the connected duct network. Air may go to occupied areas or pass through additional filtration, cooling, heating or humidity treatment. Heat recovery reduces part of the load but does not automatically achieve the final supply-air setpoint.

The exhaust fan moves air through the extract and discharge path after energy recovery. The outlet must be arranged to limit re-entry into this unit's intake or other nearby intakes. Discharge direction, wind effects and the nature of the exhaust influence rooftop placement.

Temperature, pressure and relevant humidity readings guide fan and recovery operation. Speed control, bypass logic and alarms help respond to changing demand and weather. A compatible building management system (BMS) interface can provide scheduling, operating information and agreed supervisory commands.

A fixed plate exchanger provides separate air channels and conducts heat through their dividing surfaces. Standard impermeable plates recover sensible energy without intentional water-vapour transfer. The recovery core has no moving element, although fans and actuated dampers remain part of the ventilation system.

A rotating matrix moves between the supply and exhaust streams, absorbing and releasing energy. Sensible recovery is available, while latent recovery depends on suitable media and operating conditions. The assembly includes a drive and associated controls; seals, pressure relationships and potential carryover require evaluation.

A heat pipe transfers energy through evaporation and condensation of a sealed working fluid, which may be a refrigerant depending on the design. Its passive recovery mechanism transfers sensible energy between separated air sections. Tube orientation, partitions, operating temperatures and airflow arrangement must suit the selected assembly.

Separate supply and exhaust coils are linked by a circulating liquid loop. A pump moves fluid between the coils to transfer thermal energy, allowing the air streams to remain physically remote. The arrangement adds pipework, controls and pump energy, which must be included in the recovery assessment.

Enthalpy recovery combines temperature and moisture-related energy transfer using a suitable membrane or rotary medium. It can reduce part of the outdoor-air humidity load in appropriate climates. Actual moisture transfer, contaminant compatibility and cleaning requirements depend on the selected media; enthalpy recovery is not guaranteed by rooftop mounting.

The casing protects internal components from the specified outdoor exposure while maintaining the intended air paths. Sealed panels, insulation, rain detailing and suitable corrosion protection support reliable operation. Outdoor suitability must be confirmed for the complete assembly rather than inferred from a painted exterior.

The recovery section may contain plates, a wheel, heat pipes or coils connected to an indirect recovery loop. Selection determines sensible or latent capability, resistance and service needs. Rated performance should be provided at the intended supply and exhaust conditions.

The intake may include a weather hood, louvers, bird screen and isolation damper. Its design should manage rain entry and debris while providing the required airflow. Louver resistance and intake velocity affect fan duty and weather performance.

The extract connection routes designated exhaust through the unit toward its discharge outlet. A suitable hood and any required backdraft protection help manage outdoor exposure and reverse flow. The outlet arrangement should support discharge without contaminating nearby fresh-air sources.

Pre-filters and finer filter stages can be selected to address outdoor particles and indoor-air quality requirements. Accessible housings simplify replacement and inspection. The fan selection must include the resistance of the actual filter arrangement and the allowed loaded-filter condition.

Extract-side filters help reduce dust deposition on recovery surfaces. Their classification and service needs should reflect the compatible air stream being handled. Particulate filtration does not automatically remove odours or chemical gases, or make restricted exhaust suitable for heat recovery.

The supply fan delivers the specified outdoor airflow through internal components and connected ducts. Its operating point must include filters, recovery resistance and external system losses. Efficient fan and motor selection helps limit the energy required to deliver useful ventilation.

The exhaust fan meets the extract duty through its own filter, recovery and discharge path. It may require a different pressure capability from the supply fan. Coordinated operation supports the intended supply-to-exhaust relationship and building pressure strategy.

A suitable bypass arrangement directs air around the exchanger when recovery would increase conditioning demand or an approved protective sequence requires it. Automatic dampers respond to the agreed control logic. Not every recovery technology uses the same bypass or economizer arrangement.

Where wet operation is expected, a collection pan and drain system remove condensate from the affected section. Correct orientation, slope and pressure-compatible trapping help water leave the unit. Rooftop discharge routing should avoid standing water and exposure of other building elements to leakage.

Controls operate the fans, recovery section, actuators and relevant protective functions. The electrical enclosure and cable entries must suit the rooftop environment, including temperature and moisture exposure. Speed control, alarms, sensors and BMS communications are defined by the agreed equipment scope.

Panels and joints must withstand the specified outdoor conditions while retaining structural rigidity and air sealing. Suitable door, roof and base detailing helps manage wind-driven rain. Review the manufacturer's outdoor installation provisions alongside the actual roof environment and intended exposure.

Insulation limits solar-related heat gain and winter heat loss through the casing. Appropriate vapour sealing and thermal-bridge treatment help control condensation where surface temperatures fall below the surrounding air's dew point. Insulation also supports stable air-treatment performance across rooftop temperature changes.

Casing options may include galvanized steel, pre-coated galvanized iron (GI), aluminium or suitable stainless steel. The appropriate material and coating depend on moisture, salts, chemicals and cleaning exposure. Protect joints, edges, supports and fasteners as well as broad panel surfaces.

Appropriate top-panel slope, weather-sealed joints and drainage details help shed rainwater. Intake and discharge hoods should suit their airflow and exposure. Weather protection must extend to the roof interface and connected ducts, since casing protection alone cannot prevent leaks at roof penetrations.

External coatings, exposed cables and protective coverings should suit sunlight exposure. UV-resistant provisions help prevent deterioration of seals, cable insulation and duct insulation protection. Control panels must also accommodate solar heating and the component operating temperatures expected at the installation.

Specify suitable enclosures, isolators, cable glands and sensor fittings for the outdoor conditions. Drives and control components need appropriate protection and heat dissipation. An enclosure rating should be confirmed for the supplied assembly; rooftop placement does not imply a universal IP rating.

A roof mounted plate heat recovery unit combines a fixed exchanger with the selected ventilation components and outdoor enclosure. Standard sensible cores reduce temperature-related load with no rotating recovery element. Filtration, cleaning access, leakage performance and condensation management remain important maintenance considerations.

A rooftop wheel unit can provide sensible recovery and, with suitable media, moisture recovery. It may suit larger commercial duties where the selected layout and air quality are compatible. The specification should identify the wheel drive, seals, controls and any required purge arrangement.

A heat pipe configuration uses passive fluid-based transfer instead of a rotating wheel. It can support sensible recovery where the air sections and tube orientation suit the duty. Fan energy, coil-surface cleaning and the assembly's operating limits must still be considered.

A run-around system connects rooftop or remote supply and exhaust equipment through an indirect liquid circuit. This provides layout flexibility when both air streams cannot meet at one core. Coil selection, pipework, pump duty and fluid protection determine the complete system performance.

Horizontal configurations can provide side duct connections and a practical rooftop arrangement. Duct bends, access-door travel and component withdrawal space should be coordinated around the unit. The final footprint includes service access and connected ducts, not only the casing dimensions.

Units designed with downward supply and extract connections can connect through roof openings into vertical ducts. Confirm the actual connection orientation on the selected drawings, as exhaust discharge direction may differ. The curb, duct transitions and penetration seals must match the specific arrangement.

Modular construction separates larger equipment into sections with specified filters, fans and recovery components. This can help transportation or handling where a single large package is difficult to deliver. Section joints, lifting provisions, assembly access and final weather sealing must be included in the installation plan.

A correctly selected roof curb supports the unit and provides an interface for duct transitions and weather sealing. Its geometry must match the unit base and approved roof openings. Support, insulation, flashing and anchorage should be coordinated with the roof structure and covering system.

A designed steel frame can transfer equipment reactions to suitable structural members and provide the required rooftop clearance. Member layout must reflect actual support points and service access. Corrosion protection, connections, anchorage and roof-interface details form part of the support design.

A concrete plinth may provide elevation and support where the roof structure is designed to accommodate it. Include the plinth's own weight, equipment reactions and anchorage in the assessment. Its position and surrounding drainage should permit maintenance without trapping water against the roof covering.

Appropriate elastomeric pads or spring isolators can reduce vibration transmitted from the equipment into the building. Selection depends on load, fan characteristics and required isolation. Rooftop mounts may also need restraints; vibration isolation must be coordinated with wind, seismic and connection requirements.

The installed base should meet the selected equipment's alignment and levelling requirements. Correct support helps preserve designed drain-pan slopes, fan alignment and exchanger seating. Do not rely on roof slope alone or assume every component needs the same orientation; follow the approved unit drawings.

Distinguish shipping or dry weight from operating weight. Include specified coils, filters, accessories, retained fluid and the support assembly as applicable. Obtain the selected manufacturer's weights and support reactions so the structural assessment reflects the complete installed arrangement.

Loads act through the unit's designated support points and may create concentrated reactions. A qualified structural assessment should check how those reactions transfer into beams, slabs or other members. Average weight divided by footprint is insufficient to confirm the roof's suitability.

Rooftop exposure can impose uplift and lateral loads on equipment, hoods and supports. The required anchorage depends on site conditions, building height, unit geometry and applicable design requirements. Check the equipment-to-support and support-to-structure connections as part of the complete load path.

Where the project requires seismic design, evaluate equipment anchorage, isolator restraints and connected services accordingly. The selected arrangement should allow required movement while maintaining restraint. Use the applicable structural requirements and approved design rather than a generic anchor detail.

Coordinate openings for supply and extract ducts, cables and drains before cutting or setting the unit. Avoid interfering with structural members and maintain the specified roof sealing. Penetrations need appropriate support and weather detailing without relying on sealant alone to replace a proper flashing arrangement.

Locate the intake where a suitable outdoor-air source is available. Evaluate traffic pollution, kitchen or process discharge and nearby exhaust equipment. Roof level does not automatically provide clean air; the position should reflect the actual building layout and surrounding sources.

Arrange exhaust discharge to limit recirculation into outdoor-air intakes and exposure of neighbouring areas. Consider prevailing winds, outlet direction and the discharge's composition. Discharge design should follow the application's ventilation requirements and the selected equipment's installation provisions.

Adequate intake-to-discharge separation helps prevent air short-circuiting outside the unit. Determine the necessary arrangement from the exhaust classification, outlet geometry, roof layout and applicable design criteria. A universal separation distance cannot be assigned to every rooftop HRU installation.

Weather hoods and louvers help limit rain entry while allowing the required airflow. Bird screens add debris protection but need accessible cleaning. Review louver weather performance, free area, face velocity and resistance together so weather protection does not create excessive fan duty.

Share your roof layout and ventilation requirements with Compress India to discuss equipment placement, duct connections and the installation scope before selecting the final unit.

Sensible recovery changes air temperature through the selected exchanger. Supply-side temperature effectiveness compares the change across the recovery section with the available difference between outdoor and exhaust inlet temperatures:

Temperature effectiveness (%) = [(Supply outlet temperature − Outdoor inlet temperature) ÷ (Exhaust inlet temperature − Outdoor inlet temperature)] × 100.

Use readings directly across the recovery section, excluding downstream treatment and fan heat. Unequal flows, condensation, leakage and small inlet temperature differences affect interpretation.

Latent recovery involves transferring water vapour through suitable media, such as an enthalpy wheel or selective membrane. The amount depends on moisture differences, airflow and media performance. Standard impermeable plates and conventional heat pipes do not intentionally transfer humidity between streams, even if condensation occurs on their surfaces.

Total recovery considers both temperature and moisture-related energy using air enthalpy. Suitable enthalpy equipment can reduce part of the combined outdoor-air conditioning load. Specify the test conditions and flow rates when comparing ratings, and distinguish recovery-section performance from the complete system's net electrical or fuel savings.

Sensible capacity depends on airflow, air density, specific heat and the temperature change across the recovery section. Total capacity for suitable equipment also considers the enthalpy change associated with humidity. Capacity is a thermal rate; annual savings additionally depend on operating hours, plant efficiency, fan input and auxiliary energy.

The recovery section adds resistance to the supply and extract paths. State both pressure drops at their respective selected airflows. Review effectiveness alongside this resistance, since greater recovery output may require more fan power and can change the preferred overall energy balance.

Balanced operation coordinates supply and extract quantities around the intended ventilation duty. Density differences may matter when comparing volume-flow measurements. Building pressure also depends on other fans, transfer paths and envelope leakage, so equal HRU readings alone do not guarantee neutral pressure throughout the building.

A planned supply surplus can support positive pressure in designated areas and reduce uncontrolled infiltration. The required relationship should be assessed across the full ventilation system. Recovery must be evaluated at the actual unequal airflows, including the additional fresh air that exceeds the available extract quantity.

A planned extract surplus may be required for selected containment or extraction duties. Replacement air and pressure relationships need clear design control. Suitability of the extract for energy recovery must be assessed separately, especially where hazardous, infectious or otherwise restricted exhaust is involved.

Measured airflow, fan speed and appropriate dampers are used to establish the specified relationship. VFD or equivalent fan controls can maintain required duties as resistance changes. Verify normal, part-load and protective modes without compromising minimum ventilation or the building pressure strategy.

Pre-filters intercept larger outdoor particles before they reach recovery surfaces and downstream equipment. Local dust exposure and intake placement influence the required protection. Accessible filter housings make rooftop servicing easier and help prevent avoidable fouling of the recovery core.

Finer filters can remove smaller particles according to their actual classification. Select the required stage around outdoor-air quality and the spaces served. Confirm filter seating, replacement availability and the added resistance rather than assuming any fine filter meets every indoor-air quality objective.

Some applications require higher-efficiency filtration within the complete ventilation arrangement. Check the specified class, housing integrity and permitted location for the selected equipment. Additional resistance, loaded-filter allowance and maintenance access must be included when determining whether the HRU and fans can meet the duty.

Extract-side filtration helps protect the exchanger from dust, lint and other permitted particles. It supports stable resistance and thermal performance over time. Assess the actual exhaust composition separately because particle filters do not establish compatibility with odorous, chemical or hazardous air streams.

Pressure monitoring provides an indication of filter loading and can initiate maintenance alerts. Assess readings at comparable airflow, since reduced flow may conceal increasing resistance. Appropriate alerts help avoid low ventilation delivery or excess fan power used to compensate for loaded filters.

State the required fresh-air quantity in CFM or CMH, together with its reference conditions. Occupancy, space use and ventilation criteria determine the duty. Define the minimum flow and permitted demand-control range so speed changes do not reduce required outdoor-air delivery.

Identify the extract volume available for recovery at each relevant operating condition. Account for separate exhaust systems and the intended building pressure relationship. Fan and exchanger selection should use this compatible quantity rather than the total exhaust installed across unrelated applications.

Internal resistance includes the recovery section, filters, dampers, coils and other components within the specified unit. Evaluate the actual configuration at design and relevant alternative operating points. Include the agreed loaded-filter condition when confirming the required fan duty.

External losses include connected supply and extract ducts, fittings, vertical risers, grilles and diffusers outside the equipment boundary. Define which intake and discharge items are included. Separate calculations for both networks prevent overlooked resistance or duplicate allowances.

Select the supply fan for its airflow and complete resistance using a consistent pressure basis. Check fan efficiency, motor efficiency, operating input, sound and control range. The chosen fan must remain suitable as filters load and the unit moves between normal and alternative modes.

Select the extract fan for its own recovery and discharge network. Check efficiency, sound and motor loading at the required operating points. Fan placement and coordinated control should maintain acceptable pressure differences across separating surfaces and seals.

A compatible VFD adjusts fan speed to follow the specified airflow or pressure requirement. Demand control can reduce unnecessary operation while maintaining minimum ventilation. EC fans may provide an integrated alternative; define the selected control method and how both air streams are coordinated.

A bypass directs the specified air stream around the recovery section when heat exchange would oppose the desired supply conditions. Its capacity and damper arrangement must support the intended mode. Wheel systems may use a different recovery-control arrangement, so confirm the actual equipment sequence.

Suitable outdoor air can reduce mechanical cooling demand when introduced without unwanted reheating from the exhaust. Temperature, humidity, outdoor pollution and building requirements determine when economizer operation is useful. A temperature-only decision can be counterproductive where outdoor moisture significantly increases the cooling load.

Motorized dampers allow automatic changeover or modulation according to the agreed conditions. Position feedback helps confirm that the commanded path is available. Temperature-based logic, relevant humidity assessment and BMS commands should be coordinated with local protective functions and fan operation.

Use recovery when it reduces the required heating or cooling load and bypass or reduce recovery when it does not. Summer, winter and transition-season decisions should follow actual conditions rather than calendar dates alone. Include economizer opportunities, humidity constraints and frost protection in the operating sequence.

Condensation forms when humid air contacts a surface below its dew point. Depending on operating conditions, moisture may collect in the recovery section or an included cooling section. Identify the affected areas during selection so suitable collection, drainage and material compatibility are provided.

Specify a pan material compatible with the expected water and exposure. The pan and equipment alignment should preserve the designed slope toward the outlet. Accessible collection surfaces help remove deposits and prevent standing water.

The trap arrangement must suit the pressure at the drain connection and the selected equipment instructions. Correct sizing and priming help maintain drainage without uncontrolled air leakage. Test the drain with the fans operating because shutdown drainage alone does not demonstrate satisfactory performance.

Route condensate to an approved discharge point without creating standing water around the unit or across maintenance paths. Provide suitable fall, support and access for clearing blockages. Include protection against freezing where the operating climate requires it.

Insulation, vapour sealing and thermal-bridge treatment help control condensation on casing and duct surfaces. Weather detailing should prevent rain from wetting insulation or entering the assembly. Apply these measures to joints, support interfaces and connections as well as large panel areas.

Sufficiently cold recovery surfaces can freeze moisture from humid extract air, increasing resistance and reducing airflow. Risk depends on outdoor temperature, exhaust humidity, airflow and exchanger type. Specify protection for the actual climate rather than assigning a universal frost threshold to every rooftop HRU.

Where the selected exchanger supports it, an automatic bypass sequence can reduce cold airflow through the recovery section or assist defrosting. Its operation must match the equipment design. Confirm the effect on supply temperature, ventilation delivery and pressure balance during protection.

Electric or hot-water preheating can raise incoming air temperature before the exchanger to control frost risk. Select the heater and interlocks for the approved duty. Include preheater energy in the overall savings assessment, since frost protection affects the net benefit of recovery.

Approved changes to fan operation can adjust recovery-surface conditions during frost-risk periods. The available method depends on the exchanger and control design. Any reduced supply or altered extract duty must remain compatible with minimum ventilation, pressure requirements and the building's operating needs.

Temperature readings and pressure-drop monitoring can help detect conditions associated with frost. The control sequence should define initiation, protective action, recovery and alarms. Verify sensor scaling and the manufacturer's required logic before using pressure rise alone as evidence of icing.

Outdoor-suitable casing, joints and hoods protect the ventilation components from the specified rooftop exposure. Maintaining this envelope helps prevent wet filters, insulation damage and weather-related interruptions. It is essential for commercial and industrial installations where the unit operates outside an enclosed plant room.

Coordinated supply and extract sections allow both duties to be managed within one defined ventilation arrangement. This supports recovery and airflow balance while placing much of the equipment on the roof. Centralized offices and commercial complexes can benefit where their duct networks and compatible exhaust streams suit the layout.

A correctly selected exchanger can recover a useful share of the available temperature or enthalpy difference. For rooftop installations, verified performance helps offset the recurring cost of outdoor-air treatment. Compare effectiveness with pressure drop and auxiliary energy for buildings with substantial ventilation hours.

Sensible equipment transfers temperature energy, while suitable enthalpy media also transfer water vapour. Matching the recovery type to local weather and exhaust conditions can improve the value of rooftop ventilation. Moisture-sensitive applications still require assessment of final humidity control and media compatibility.

Suitable units can combine pre-filtration with the specified finer stages. These protect exposed rooftop equipment from intake particles and support the indoor-air quality objective. The benefit depends on correct classification, airtight seating, fan allowance and accessible replacement arrangements.

Efficient fans and motors reduce the power needed to move air through the recovery section and building ducts. Rooftop risers and weather components can add resistance, making a verified operating point important. Select the arrangement around actual airflow, pressure and sound requirements.

Where provided, compatible drives allow fan speed to match permitted ventilation demand. This can reduce unnecessary airflow and associated power during lower occupancy. Coordinating both air streams is particularly useful in rooftop systems serving variable-use offices, retail or educational buildings.

A specified bypass can avoid heat exchange when outdoor air provides favourable free cooling or a protective sequence requires an alternative path. This makes operation more adaptable across seasons. The rooftop layout must include the necessary airflow capacity, actuators and weather-protected controls.

Appropriate pans, outlets and traps collect and remove water where condensation is expected. On a roof, planned drain routing also limits water accumulation around equipment and access paths. This supports dependable operation in applications with wet recovery or included cooling sections.

Suitable metals, coatings and protected connections help the unit withstand its specified outdoor environment. This matters where rooftop equipment encounters moisture, pollution or coastal salts. Material selection and periodic inspection help preserve casing integrity, service access and the reliability of ventilation components.

Appropriate enclosures and cable entries protect controls and power components against the identified rooftop exposure. Thermal management keeps drives and electronics within their intended operating conditions. This supports dependable fan, damper and alarm functions in continuously operated outdoor ventilation equipment.

A compatible interface provides the agreed operating readings, alarms and commands to the central BMS. Facility teams can monitor remote rooftop equipment and coordinate schedules without relying solely on local inspection. Useful data include temperature, pressure, fan status and recovery or bypass mode.

When incoming outdoor air is hotter than suitable exhaust, recovery can pre-cool the fresh air before mechanical treatment. A sensible core reduces temperature-related load, while suitable enthalpy equipment may also reduce moisture load. Actual benefit depends on inlet conditions and the selected recovery performance.

Warm exhaust can pre-heat colder incoming air, reducing the downstream heating requirement. Assess this benefit across winter operating hours and actual airflows. Where frost protection is required, include its energy use rather than assuming all recovered heat becomes a net saving.

Useful recovery can lower conditioning energy associated with outdoor-air delivery. Compare that reduction with both fan inputs and any pump, wheel-drive or preheater energy. The complete operating strategy determines whether the proposed rooftop system provides the expected net benefit.

Locating the unit on a suitable roof reduces the equipment footprint within indoor service areas. This can help developments where internal space is limited or valuable. Roof support, distribution routes and accessible servicing must be considered alongside the space saved indoors.

A coordinated rooftop system can serve connected ventilation zones through central supply and extract networks. This can simplify scheduling and performance monitoring. Each zone's airflow, filtration and pressure requirements must still be met through appropriate distribution and controls.

Conditioned extract air carries temperature and, where relevant, moisture-related energy. Suitable recovery uses part of that available difference before discharge. Its value is greatest when compatible exhaust and outdoor-air treatment operate simultaneously under favourable conditions.

Recovery can reduce the conditioning penalty of delivering the fresh air required by the building. It supports energy-conscious ventilation without replacing the need to meet the actual rate. Fan capacity, filtration and downstream treatment must be selected for the intended airflow.

Large buildings may have substantial ventilation loads and useful concurrent exhaust flows. Rooftop layouts can accommodate centralized or modular recovery equipment where structure and access permit. Zoning, duct resistance, acoustics and exhaust compatibility determine the appropriate system arrangement.

An HRU may precondition outdoor air for existing AHUs, PAUs or other treatment equipment. Assess duct capacity, controls and available exhaust before defining the connection. A ventilation HRU integrated with VRF conditioning is separate from a refrigerant-system heat recovery function.

New construction can coordinate roof support and duct routes from the start. Retrofit work can use available roof space where the structure and existing services permit. Both require a defined recovery duty, weatherproof interfaces and maintainable access to turn available exhaust energy into useful performance.

Central systems coordinate required supply airflow with compatible extract from connected spaces. Recovery can reduce treatment load while placing the main equipment outside indoor plant rooms. Intake filtration and extract-side core protection should suit local air quality. Duct distribution and roof access must support the full selected duty.

Buildings with substantial outdoor-air requirements may offer useful recovery when sufficient compatible exhaust runs at the same time. Select filtration for the spaces served and ambient pollution. Rooftop placement can accommodate the required package, but high airflow makes pressure losses, sound and structural support particularly important.

Office supply airflow follows occupancy and ventilation criteria, while suitable general extract may provide a recovery source. Outdoor particulate filtration and accessible extract filters protect performance. Rooftop equipment can preserve indoor service space and support central scheduling. Assess part-load operation and actual exhaust availability outside peak occupancy.

Retail ventilation changes with footfall, tenant use and opening hours. Compatible extract can offset outdoor-air thermal load, with filtration selected for the operating environment. Roof installation can support larger air-handling packages. Kitchen, odorous and restricted exhaust must be assessed separately from ordinary comfort ventilation.

Hotel fresh-air and extract requirements vary across guest, public and service areas. Approved exhaust streams may offer recovery over extended hours. Humidity, filtration and odour separation influence selection. Rooftop placement can reduce indoor equipment demand while keeping service access and acoustics coordinated with guest comfort.

Classroom supply and suitable general extract often follow academic occupancy schedules. Recovery can reduce conditioning load during operating hours, with filters addressing local outdoor particles. Rooftop units may free internal space for teaching areas. Laboratories and workshops need separate exhaust evaluation, and access should support maintenance outside busy periods.

Suitable support or nonclinical spaces may allow recovery where the approved ventilation design permits it. Supply rates, exhaust classification, pressure relationships and filtration must suit each area. Rooftop placement can support central equipment access, but infection-control restrictions and acceptable leakage performance take priority over the energy opportunity.

Industrial comfort and support ventilation may use compatible exhaust to precondition required outdoor air. Select filtration, recovery media and coatings around actual contaminants and condensate. Roof installation can keep major ventilation equipment outside production space. Hazardous, corrosive or process-specific exhaust needs dedicated assessment before connection to recovery equipment.

Conditioned offices, staff areas or selected logistics zones may have useful simultaneous supply and extract operation. Dust exposure affects filtration and service requirements. Rooftop placement can preserve working floor space. Evaluate temperature differences and schedules carefully because an unconditioned warehouse may offer little recoverable ventilation energy.

Rooftop installation can provide a location for required fresh-air and compatible extract duties where indoor equipment space is restricted. The recovery and filter selections remain governed by the actual building use. Include roof loading, ducts, weather protection and service clearances so saving indoor space does not create inaccessible equipment.

Existing systems require measured or documented supply and extract duties, exhaust suitability and current duct resistance. Recovery may reduce ongoing conditioning load where those inputs support it. Select filtration for the upgraded duty and assess roof support and openings. Rooftop placement can create an installation option without requiring a new indoor plant room.

Property teams can assess rooftop recovery around tenant ventilation duties and available general extract. Suitable roof space may preserve rentable or indoor service areas. Intake pollution, filter servicing and pressure zoning influence selection. Compare expected energy savings with installation, roof-interface and maintenance costs over the intended operating period.

Hospitality facilities often have extended ventilation hours and several distinct air-quality zones. Only suitable exhaust should be used for recovery. Rooftop installation can consolidate equipment outside guest areas, while filtration, moisture control and noise require attention. Assess each zone's operating schedule before combining supply and extract duties.

Retail properties need airflow that follows occupancy and the use of individual tenancies. Compatible conditioned-area extract may support recovery, with roof space accommodating central equipment. Filtration and odour separation must account for local sources. Tenant kitchens and other specialized exhaust should not be assumed compatible with general ventilation recovery.

Large offices can combine significant fresh-air requirements with suitable general extract. Rooftop units may provide space for efficient central treatment and coordinated BMS scheduling. Outdoor particle loading and changing occupancy influence filtration and controls. Specialized data-hall or equipment ventilation should be assessed separately from office comfort ventilation.

Schools and colleges need ventilation aligned with classroom occupancy, holidays and special-use areas. Suitable general extract provides recovery during occupied periods. Rooftop placement can preserve internal teaching and service space. Filter selection should suit local air quality, and laboratories or workshops require separate contamination assessment.

Healthcare ventilation must follow the requirements of the actual clinical or support space. Permitted exhaust may offer recovery, while rooftop equipment can support larger centralized arrangements. Filtration, air separation, infection-control considerations and pressure relationships govern suitability. Energy recovery must remain within the approved ventilation strategy.

Selected pharmaceutical support areas may provide compatible exhaust for fresh-air recovery. Rooftop installation can help accommodate treatment equipment outside controlled work areas. Product contamination, cleanroom pressure cascades, filtration and cleaning requirements need review. The chosen recovery arrangement must align with the site's approved ventilation and qualification requirements.

Manufacturing sites may recover energy from suitable comfort or support exhaust where outdoor-air treatment operates concurrently. Roof location can preserve production space. Dust, oils, chemical exposure and condensate determine filtration and material selection. Process extraction must be evaluated independently so recovery does not compromise its required function.

Ventilation requirements differ across offices, production and hygiene-controlled areas. Compatible extract may support recovery, with rooftop placement reducing indoor equipment demands. Moisture, grease, odours and cleaning exposure influence air-quality decisions. The recovery technology and filtration must suit the designated area without disturbing contamination control or pressure relationships.

Recovery opportunities depend on conditioned zones, occupancy and available extract air. Roof location can preserve storage and circulation space. Dust filtration, frequent door opening and seasonal operation affect performance. Evaluate the actual ventilation duty rather than assuming that a large warehouse footprint warrants an HRU.

Passenger facilities may require substantial fresh-air delivery over extended operating hours. Compatible conditioned-area exhaust can provide energy recovery, while roofs may offer space for central equipment. Intake pollution, filtration, redundancy and maintenance access need careful coordination. Restricted exhaust streams and operating-continuity requirements influence the final system arrangement.

Establish outdoor-air demand from occupancy, space use and the applicable ventilation criteria. State design and minimum quantities in CFM or CMH with reference conditions. These requirements guide unit sizing and define the permitted range for demand-based operation.

Identify compatible extract streams and their available flow during fresh-air operation. Include separate exhaust systems and intended building pressure in the assessment. The available recovery duty may be smaller than the total exhaust quantity across the building.

Provide summer dry-bulb temperature, wet-bulb temperature or the appropriate humidity data, and winter design temperature. These conditions establish sensible and latent treatment loads. Seasonal operating conditions help evaluate recovery, economizer operation and frost protection beyond a single rating point.

Provide extract temperature, humidity, contaminants and operating schedule. Confirm that the stream is permitted and compatible with the proposed recovery equipment. These inputs determine the useful energy difference, filtration, materials and contamination-control requirements.

Compare plates, rotary wheels, heat pipes and run-around coils against the airflow, space and air-separation requirements. Decide whether temperature-only recovery or moisture transfer is useful. Use equipment-specific performance and compatibility data rather than assuming one technology is best for every roof installation.

Set the required effectiveness at stated inlet conditions and flow rates. Assess climate, operating hours, energy objectives and the project's acceptance criteria. Higher recovery should be considered together with pressure losses, auxiliary energy and the resulting operating cost.

Calculate internal losses from filters, the exchanger, dampers and included treatment sections. Calculate connected duct, fitting, terminal and riser losses separately for both streams. State the pressure basis and boundaries clearly so the fan duty includes each component once.

Select both fans independently for their complete airflow and resistance duties. Review fan and motor efficiency, sound, loading and speed-control compatibility. VFD or EC arrangements should support the required balance and remain suitable across the defined operating range.

Check casing dimensions, connection positions, duct routing and door clearances against the available layout. Include filter and recovery-section removal space, safe maintenance paths and delivery or crane access. A unit that fits within the roof footprint may still be unsuitable if it cannot be serviced.

Obtain operating weight, support reactions and mounting details for the selected unit. The structural assessment should include the curb or frame, wind actions and other applicable loads. Confirm the support-to-structure load path rather than selecting equipment from an approximate roof weight allowance.

Review rain exposure, sunlight, dust, corrosive pollution and coastal salts where relevant. Match casing, coatings, hoods and electrical protection to those conditions. Assess the nearby intake environment and service frequency as part of the selection.

Specify fan control, recovery or bypass logic, sensors, alarms and scheduling. Define humidity monitoring where relevant and energy monitoring where required. CO2-based demand control may suit occupied comfort zones, but minimum ventilation and other air-quality requirements must remain satisfied.

For integration with chilled-water AHUs, PAUs, treated fresh-air units or buildings using VRF conditioning, provide the existing air-treatment and control details. Compress India can use these inputs to define the ventilation integration and quotation scope.

Review sensible and, where applicable, latent effectiveness at the actual inlet conditions. Climate and operating hours influence how often the rated opportunity occurs. Compare seasonal useful recovery rather than relying solely on a peak laboratory percentage.

The heat-capacity rates of both streams affect transfer and outlet conditions. Maintain the intended airflow relationship while preserving building pressure and minimum ventilation. Evaluate recovery performance at actual part-load and unequal-flow conditions, not only a nominal balanced duty.

Fan and motor efficiency determine how much input is required to overcome unit and duct resistance. EC or suitable plug-fan options may be relevant, but compare the complete assembly at its operating point. Component labels alone do not establish the lowest system energy consumption.

Where permitted, variable speed can reduce unnecessary airflow during lower occupancy. Maintain the required supply-to-extract relationship and ventilation minimums. Savings depend on the actual fan, system resistance and control sequence; they cannot be inferred from the presence of a drive alone.

Core geometry and face velocity influence both resistance and recovery performance. A lower-loss section can reduce fan duty but may need more space or have different effectiveness. Compare alternatives at the same flow, inlet conditions and complete filter arrangement.

Loaded filters increase resistance and can either reduce airflow or increase the power needed to maintain it. Timely replacement also limits core fouling. Use condition and pressure trends at comparable airflow to define service needs and avoid unnecessary operating losses.

Use bypass or the appropriate recovery-control method when heat exchange would increase conditioning demand. Free cooling decisions should account for temperature, humidity and outdoor-air quality. Confirm that the alternative path maintains required airflow and does not introduce excessive resistance.

Roof exposure can create casing and duct heat gain or loss that reduces useful delivered performance. Appropriate insulation, sealed vapour barriers and protected joints limit those effects. Maintaining weatherproof coverings helps retain insulation performance over time.

Monitor schedules, airflow, temperatures, relevant humidity, bypass status and alarms to identify avoidable operation or declining performance. Where metering is available, compare energy use with an agreed baseline. Assess payback from additional installed cost and net annual savings, including fan and auxiliary energy and maintenance differences.

Confirm roof suitability using selected equipment weights, support reactions and applicable load combinations. The structural design should account for frames, curbs, anchorage and relevant environmental actions. Complete this assessment before committing to the equipment location or roof openings.

Plan lifting around verified unit weights, approved lifting points, crane access and the site's actual constraints. Use a competent lifting team and the equipment instructions for rigging and weather limits. Coordinate roof preparation and landing access before the unit is brought into position.

Install the approved support arrangement at the designated structural locations. Check dimensions, alignment, anchorage and required roof weather detailing. Complete relevant duct transitions and access provisions without obstructing the unit's specified seating or service paths.

Set the unit to its approved alignment requirements so designed drain slopes and component positions are maintained. Check support at all required points. An uneven base can affect drainage, casing joints and rotating-component alignment.

Install the selected isolators and any required restraints according to the support design. Confirm loading and connection compatibility. Ducts, drains and other services should not bypass the isolation through rigid arrangements that transmit vibration into the building.

Connect the supply path to the correct unit opening with suitable transitions and support. Seal joints and check that the duct arrangement does not load or distort the casing. Provide the specified insulation and measurement access.

Connect only the approved extract streams to the designated opening. Use supported, sealed transitions suited to the airflow and pressure duty. Maintain the intended separation from supply air and allow access for balancing or inspection where specified.

Install the selected hood, louvers, screens and damper in their approved orientation. Verify the intake location against nearby contamination sources. Preserve drainage and cleaning access without reducing the required intake area.

Fit discharge components according to the selected outlet arrangement and outdoor exposure. Check direction, nearby intakes and potential recirculation. Include backdraft or weather protection where specified without creating an unaccounted pressure loss.

Coordinate flashing, upstands and compatible sealing with the roof covering system. Detail ducts, cables and drains individually where needed. The final interface should accommodate movement and drainage while maintaining the roof's intended weather performance.

Insulate exposed ducts for the intended air temperatures and ambient conditions. Protect insulation with suitable weatherproof cladding and sealed joints. Supports, terminations and access points should retain both thermal continuity and water-shedding performance.

Provide the specified trap, fall, support and discharge route for each wet section. Keep drains accessible for service and protect them where freezing is relevant. Verify operation under unit pressure rather than only with the fans off.

Connect power to the actual fan, drive, heater and control requirements of the supplied equipment. Provide the approved isolation, protection and earthing. Qualified electrical checks should confirm suitability before operational commissioning.

Use cable entries and glands appropriate to the enclosure and outdoor exposure. Seal unused openings and protect cables from damage and sunlight as specified. Arrange entry and routing so water is not directed into the electrical assembly.

Install sensors at the defined measurement positions with suitable exposure protection. Temperature and humidity readings should represent the intended air condition, while pressure taps must suit their measurement purpose. Incorrect locations can undermine both recovery verification and control decisions.

Connect the agreed communication interface and verify point assignments, scaling and control priority. Keep local protective functions and supervisory commands coordinated. Document the final configuration so facility teams can interpret readings and alarms correctly.

Provide an appropriate roof access route and working space around service panels. Include filter withdrawal, fan removal and recovery-component access. Plan maintenance around the unit's actual location, roof-edge conditions and the site's required access provisions.

For roof mounted HRU installation in an existing building, provide roof drawings, duct layouts and photographs. Compress India can help define the equipment integration and site work needed for a reviewable quotation.

Use duct materials, sheet-metal construction and protective finishes suited to the pressure duty and outdoor environment. Include compatible joints, fasteners and supports. Exposed ducts must retain their integrity under the specified weather and movement conditions.

Appropriate insulation limits heat gain, heat loss and external condensation. Select its thickness and vapour-control arrangement from the actual temperatures and humidity conditions. Maintain continuity at connections, supports and fittings.

Cladding protects insulation from rain, sunlight and physical exposure. Detail laps, joints and terminations to shed water and limit ingress. Wet insulation can lose thermal performance and conceal corrosion beneath the covering.

Suitable flexible connections help accommodate equipment vibration and permitted movement. Check airtightness and application compatibility. They should not carry unsupported duct loads or be used to compensate for major alignment errors.

Support ducts and coordinate openings with structure, flashing and roof sealing. Avoid transferring unintended duct loads into the unit or waterproofing interface. Allow the movement required by the approved connection detail.

Seal joints and access points to the specified duct performance requirement. Where required, use pressure testing to verify the completed network. Leakage can reduce delivered ventilation, disturb balance and waste fan and conditioning energy.

Measure the supplied outdoor-air quantity using the agreed method and suitable instruments. Compare it with the selected duty. Record fan speed, damper positions and filter condition alongside the measurement.

Measure the extract quantity through the designated recovery path. Confirm connected streams and distinguish independent exhaust systems. Record the operating mode so the reading can be meaningfully compared with the supply flow.

Check the measured supply-to-extract relationship against the required ventilation and pressure strategy. Include relevant transfer paths and other operating fans. Verify alternative modes where they change the intended balance.

Measure supply-side pressure at the specified points and compare with the fan selection and network calculation. Unexpected losses may indicate restrictions or incorrect settings. Record airflow and measurement locations with the result.

Check pressures through the extract and discharge path using the agreed basis. Confirm that the fan meets its duty and the recovery assembly's pressure limits are respected. Investigate unexplained departures from the design.

Assess recovery under stable operation using measured flows and conditions immediately across the exchanger. Compare with expected performance at those conditions. Account for condensation, leakage, fan heat, measurement uncertainty and small inlet temperature differences.

Record the inlet and outlet temperatures of both air streams at defined points. Avoid positions distorted by downstream coils or unrelated heat gains. These readings support recovery assessment and a useful commissioning baseline.

For moisture-transfer equipment, measure humidity at the specified inlet and outlet positions. Combine humidity and temperature data on a consistent basis when assessing enthalpy performance. Verify sensor accuracy before drawing conclusions about latent recovery.

Measure loss across the supply and extract sides separately at the actual airflow. Compare with the selected recovery assembly. High resistance may indicate fouling, restricted passages, wet-operation effects or incorrect flow distribution.

Record the resistance of each filter bank in its initial installed condition. Check filter class, seating and pressure connections. Use the readings as a maintenance baseline, with alerts set for the approved operating criteria.

Check rotation, current, speed, vibration, mounting and sound at the intended duty. Verify motor loading against supplied limits. Record separate supply and extract results and investigate unstable or abnormal operation.

Verify commands, feedback, speed limits and required fault responses. Confirm that coordinated fan control follows the approved sequence. For an EC arrangement, perform equivalent checks on the supplied interface and control functions.

Check actuator travel, end positions, feedback and the actual alternative airflow path. Verify the conditions that command recovery or bypass. Confirm that changeover preserves the required ventilation and acceptable supply conditions.

Verify pan collection and drainage with the unit operating as intended. Check traps, discharge flow and absence of standing water or leaks. Include all recovery and cooling sections that can collect condensate.

Inspect casing joints, access doors, hoods, cable entries and exposed duct protection. Check roof-interface detailing against the approved arrangement. Rectify gaps, damaged finishes and incomplete seals before handover.

Check for evidence of water entering the casing or roof interfaces using an inspection or test method appropriate to the assembly. Distinguish rain entry from condensate faults. Do not assume outdoor construction permits unrestricted pressure-water testing.

Check temperature, humidity and pressure readings against suitable references. Verify signal ranges, units, offsets and controller scaling. Correct measurement errors before accepting performance calculations or relying on automatic sequences.

Test normal start-up, shutdown, scheduling, recovery control, alarms and relevant protective modes. Include approved frost protection where applicable. Document final setpoints and confirm that equipment interlocks operate as designed.

Confirm the agreed values, commands, operating states and alarms appear correctly in the BMS. Check units, scaling and local control priority. Retain the final points list and settings for operational handover.

Request a defined rooftop HRU commissioning scope from Compress India, including the required measurements, inspection records and performance handover documents.

Inspect recovery surfaces and accessible passages for fouling, corrosion and physical damage. For wheel systems, check media, seals and rotation as specified. Compare observations with pressure and recovery trends to identify emerging performance loss.

Use the approved method for the actual plate, membrane, wheel, heat pipe or coil assembly. Chemicals, water pressure and temperature limits vary by construction. Do not assume one cleaning procedure is appropriate for every recovery technology.

Replace intake filters according to condition, pressure trends and equipment instructions. Use the specified size and class, and check frame sealing. Correct replacement protects both the recovery section and the supplied spaces.

Inspect extract filters for dust and other permitted loading. Replace them before resistance or deterioration compromises airflow and core protection. Confirm that the handled exhaust remains within the suitability assumed during selection.

Check cleanliness, mounting, vibration, airflow and operating readings. Verify speed commands and accessible connections. Deposits or damage can change the fan's duty and should be addressed using the approved service procedure.

Inspect the extract fan for fouling, wear and abnormal vibration. Compare its airflow and input with the commissioning baseline. Reduced extract duty can affect both recovery and the intended pressure relationship.

Check operating current, temperature indications, mounting and relevant electrical condition. Follow the manufacturer's lubrication and bearing instructions where applicable. Investigate abnormal sound or overheating rather than judging condition only from continued operation.

For belt-driven equipment, inspect belt condition, alignment and tension. Check serviceable bearings according to the supplied instructions. Direct-drive fans have no fan belts, and sealed bearings should not receive unapproved lubrication.

Inspect blades, seals, linkage and actuator operation. Verify travel and position feedback where fitted. A stuck or leaking bypass can reduce useful recovery or impose unwanted heat transfer during free cooling.

Remove deposits using a suitable approved method and check pan condition and slope. Confirm the outlet remains clear. Accessible, clean collection surfaces reduce standing water and make drainage faults easier to identify.

Inspect piping and traps for blockage, damage or loss of priming. Verify drainage under operating pressure. Check any specified frost protection and ensure rooftop discharge paths remain free and appropriately supported.

Remove accumulated debris from hoods, louvers and bird screens without damaging the weather protection. Check attachment and drainage details. Restricted intake or discharge openings can raise resistance and reduce ventilation performance.

Check panels, joints, supports and exposed finishes for damage or deterioration. Inspect insulation coverings and weather detailing. Repair defects using materials and methods compatible with the selected casing and outdoor exposure.

Inspect access-door seals, latches and panel seating after service. Damaged gaskets can allow air leakage or rain entry. Keep replacement seals compatible with the unit and maintain the required compression and closure arrangement.

Inspect exposed edges, joints, fasteners, supports and areas around drains for corrosion. Coastal or polluted environments may require closer condition-based monitoring. Identify and treat coating damage before deterioration affects weather or structural integrity.

Qualified service personnel should check enclosure condition, cable entries, moisture signs and relevant connections. Confirm thermal management and protective provisions remain suitable. Follow the equipment's isolation and inspection requirements when accessing electrical components.

Check sensor locations, pressure tubes and indicated readings against suitable references. Verify ranges and controller scaling. Incorrect readings can lead to poor recovery decisions, false alarms and misleading estimates of energy performance.

Review airflows, inlet and outlet conditions, pressure losses and operating input at comparable duties. Compare with the original baseline and expected seasonal performance. This helps identify fouling, wheel or bypass faults, imbalance and measurement errors.

For a roof mounted HRU maintenance or AMC enquiry, share the unit model, roof access details, operating hours and service history. Compress India can assess the required HVAC maintenance scope and quotation basis.

Dirty surfaces, damaged media, airflow changes and bypass faults can reduce recovery. Wheel rotation or drive issues may also matter where applicable. Verify inlet conditions and sensor accuracy before selecting cleaning, repair or recovery-component replacement.

Loaded filters, excessive duct resistance, fan faults or incorrect damper positions can reduce supply flow. Check commands and measured pressures alongside the actual quantity delivered. Correct the underlying restriction or fault rather than compensating indefinitely with higher fan speed.

Different filter loading, duct resistance, speed settings or damper positions can change the intended relationship. Measure both flows and review other operating exhaust systems. Restore the required ventilation and pressure strategy rather than assuming equal fan speeds produce equal airflow.

Fouled exchangers, dirty filters and airflow above the selected duty can increase resistance. Wet operation or restricted paths may also contribute. Compare measurements at the actual flow with the selection data and inspect the affected sections.

Damaged door seals, hood faults, casing joints or roof penetration details can permit water entry. Inspect the source and distinguish it from condensate leakage. Correct the relevant weather interface without assuming that sealing one visible joint resolves the entire problem.

Moisture, coastal salts, pollutants and damaged coatings can accelerate deterioration. Inspect vulnerable edges, fasteners and areas where water collects. Repair suitability depends on the material condition and exposure; significant damage may warrant panel or equipment replacement assessment.

Blocked piping, incorrect traps or poor unit alignment can prevent drainage. Check the collection section and discharge route under operating pressure. Restore the designed flow path and assess any wet insulation or corrosion caused by repeated leakage.

Fan imbalance, motor or bearing issues, unsuitable isolation and high duct velocity can increase noise or vibration. Check equipment operation and the support arrangement together. Rigid service connections or poor duct support can also transmit vibration into the building.

Excess airflow, dirty filters, high network losses or unsuitable control logic can increase operating input. Review recovery output and both fan duties together with auxiliaries. Compare repair, control improvement and replacement options using their effect on net energy and maintenance cost.

For roof mounted HRU repair or troubleshooting, provide the observed fault, unit details, current readings and maintenance history. A defined assessment helps establish whether service, retrofit or replacement is appropriate.

Air separation depends on the selected exchanger, partitions, seals and operating pressures. Fixed passages reduce intentional mixing but do not establish zero leakage. Specify acceptable transfer characteristics and maintain assembly integrity throughout installation and service.

Classify the proposed extract and identify odours, chemicals and process contaminants. General comfort exhaust may be suitable where the design permits it, while other streams need special evaluation. Ordinary particle filtration does not automatically make contaminated air acceptable for recovery.

Rotary wheels can carry entrained air between streams, in addition to possible seal leakage. Media-related contaminant transfer may also need assessment. Pressure relationships, purge provisions and equipment suitability influence the result; a purge arrangement should not be presented as eliminating every transfer mechanism.

Protect the outdoor-air source from the unit's own exhaust and nearby pollution sources. Evaluate intake position, discharge geometry and wind effects across the roof. Filters complement this design but do not replace suitable source separation.

Laboratories, isolation areas, hazardous processes, chemical exhaust and heavily contaminated streams require application-specific review. The acceptable technology may differ from ordinary office ventilation. Confirm permitted recovery, leakage and pressure requirements before connecting such streams to the proposed equipment.

Define supply and extract flows, climate conditions and required effectiveness before selecting the recovery assembly. Include humidity where latent performance matters. Clearly stated inputs allow meaningful comparison of proposals and make later performance validation more useful.

Review technology, rated recovery, resistance, media compatibility and air-transfer characteristics. Consider both normal and alternative operating conditions. The preferred arrangement should meet ventilation and contamination requirements while providing a useful net energy benefit.

Select fan duties using actual exchanger, filter and network resistance. Check motor input, loading, sound and speed-control range. Coordinate both fans so operating pressures remain suitable for the recovery assembly and the intended building strategy.

Coordinate operating weight, support reactions, mounting and applicable wind or other structural requirements. Match the unit base with the approved curb or frame. Include anchorage, access and weather interfaces in the installation design rather than treating support as an isolated equipment detail.

The technical submission should identify casing, insulation, recovery assembly, fans, motors, filters, dampers and controls. Confirm their suitability for the handled air and outdoor exposure. Documented components provide a clear basis for acceptance, servicing and replacement.

Check casing seals, top-panel detailing, intake and discharge protection, coatings and electrical enclosures. Coordinate these with roof penetrations and exposed duct coverings. Quality inspection should cover the complete installed envelope, not only the equipment as delivered.

Confirm the sourcing route in the quotation: direct manufacture, custom construction through a manufacturing partner, selected OEM supply or engineering and integration to the required duty. Identify the actual equipment manufacturer and recovery-component origin. Compress India's installation and integration scope, and the manufacturer's performance and warranty responsibilities, should be documented separately rather than assumed from the brand name.

Inspect recovery components, casing, fans, filters, dampers, drains, electrical items and controls against the approved submission. Check damage, seating, connections and access provisions. Record identified defects and their correction before operational acceptance.

Validate supply and extract quantities, temperature or enthalpy recovery, pressures, electrical input and control functions at defined conditions. Distinguish manufacturer ratings from site measurements. A documented acceptance basis and operating baseline support useful follow-up assessment throughout the equipment's service life.

Apply the relevant recovery-performance test basis, filter classification, duct requirements and electrical provisions for the actual equipment. Structural, wind and seismic requirements depend on the installation and project. Any certification claim should identify the supplied model and supporting evidence; one rating or standard should not be presented as covering every rooftop configuration.