Procedure For Air Handling Units Pre-Commissioning and Commissioning Method Of Statement

Below is a detailed procedure which can be used for Air Handling Units pre commissioning and commissioning activities for AHU.

Pre-Commissioning Procedure For AHU

Ensure that the AHU installation is complete and mechanical completion is approved. Ensure that no damage occurs between mechanical completion & precommissioning. Sealing between the access panels & the frames shall be checked to ensure that there is no leakage of air.

Repair all damages to the equipment finish paint. Check AHU installed as per the approved shop drawings and manufacturer’s instructions. Verify that proper thermal overload protection is installed in motors, starters and disconnects. Check all chilled water piping, connected to AHU is with proper valve package, drain, air vents, instruments, etc as per the approved shop drawing.

  • Lubricate bearings, pulleys, belts and other moving parts with factory recommended lubricants.
  • Check VAVs/CAVs with controls & wiring done as per requirement of specification.
  • Check all grilles / diffusers are fixed.
  • Check all VCDs,BDs and fire dampers are open.
  • Check all motorised dampers are installed & connected with power supply & controls properly.
  • Check intake dampers are at correct position.
  • Check filters are clean and fixed properly (Panel & Bag filters)
  • Check for proper electrical power, control panel, VFD and earthing connections as per manufacturer’s recommendations. Field wiring to be pre-tested for continuity and insulation resistance.
  • Disconnect drive motor, verify proper rotation direction, free fan wheel rotation and smooth bearing operations. Reconnect fan drive system, align belts and install belt guards.
  • Check the static & dynamic balancing of the fan impleller.
  • Set earth leakage and overload relays as per motor nameplate rating.
  • Check for proper drain of condensate.
  • BMS & Fire Alarm interface shall be checked in line with their procedures.

Air Handling Unit AHU Precommissioning Method

Commissioning Of Air Handling Units AHU

  • Ensure that all the precommissioning checks are carried out successfully.
  • Start AHU and run for 5 minutes.
  • Measure air flow in the main supply air duct and adjust, if required to set design value.
  • Measure air flow in the return & fresh air and adjust, if required to set design value.
  • Similarly measure air flow in all the branches / outlets. Set to correct value by adjusting splitter damper, volume control damper, etc in the ducts.
  • Measure the supply & return air temperature & record it.
  • Measure the Inlet & outlet water temperature & record it.
  • The cooling performance shall be calculated & established using the following formula .
    Capacity (KW) = Flow (lps) X (Outlet CHW temp (oC)- Inlet CHW temp(oC)/0.239.
  • The motorised valve shall be checked for proper operation based on the signal from the return air temperature sensor vide DDC controller.
  • Check the condensate drains freely & the slope of the condensate drain pipes is from 1 to 3% & the drain trap is serviceable.
  • Record all readings in the final performance check list.
  • Commissioning of VFDs & controls shall be in line with the approved separate procedure.

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