Primary Air Handling Units (PAU)

Primary Air Handling Units (PAU) are centralized air treatment systems designed to handle and condition 100% fresh outdoor air before distributing it to multiple zones or integrating with terminal cooling units such as FCUs, VRF indoor units, or AHUs. Unlike TFA units, PAUs are larger-capacity systems integrated into centralized HVAC infrastructure to manage high fresh air volumes with precise temperature and humidity control.

PAUs are commonly installed in commercial office buildings, IT parks, shopping malls, hospitals, airports, hotels, industrial facilities, and institutional buildings. These systems ensure centralized fresh air treatment, controlled humidity levels, multi-stage air filtration, pressure management, and reduced latent load on terminal cooling systems.

Unlike Treated Fresh Air Units (TFA), which are often standalone units serving defined areas, PAUs are typically larger-capacity systems integrated into centralized HVAC infrastructure. PAUs manage high fresh air volumes with precise temperature and humidity control, while TFAs are more localized in their application.

Common causes include insufficient dehumidification, high indoor humidity complaints, coil performance issues, low airflow, fan motor failure, drain overflow problems, sensor malfunction, refrigerant leakage (DX systems), and control panel faults. We provide rapid corrective maintenance with root cause analysis to restore centralized fresh air performance.

Our installation includes PAU unit placement and alignment, cooling coil integration (DX or chilled water), pre-cooling and dehumidification coil installation, multi-stage filtration, mixing box installation, fresh air intake louvers, drain tray and condensate piping, duct fabrication and distribution, acoustic lining installation, electrical panel wiring, control panel and sensor integration, and vibration isolation mounting.

We install and maintain DX Based Primary Air Handling Units, Chilled Water Based PAU Systems, Modular PAU Units, High Static Pressure PAUs, Low Temperature Dehumidification PAUs, and Roof Mounted PAU Units. System selection depends on building size, HVAC integration strategy, and humidity control requirements.

Yes, we execute retrofitting services including coil capacity upgrades, filtration stage enhancement, addition of HEPA filtration, reheat module installation, energy-efficient fan retrofitting, control logic modernization, and BMS integration upgrade. Retrofitting improves humidity control, filtration quality, and system efficiency.

We provide temperature and humidity sensor integration, BMS integration, demand-based fresh air modulation, VFD integration, remote monitoring dashboards, and alarm and fault indication systems. Automation ensures stable performance and optimized energy consumption.

Our AMC and maintenance services include coil cleaning, filter replacement, drain line cleaning, sensor calibration, refrigerant pressure inspection (DX systems), electrical panel inspection, airflow performance verification, and insulation inspection. Customized AMC plans are structured for commercial and institutional buildings.

PAUs achieve dehumidification by cooling outdoor air below dew point temperature, removing condensate for humidity control, with optional reheat to maintain supply temperature. Design considerations include inlet outdoor air conditions, coil apparatus dew point, target supply air temperature, and target relative humidity. This ensures reduced humidity in occupied spaces and prevents condensation on terminal units.