The purpose of this procedure is to define the step by step method to implement the correct practices for the precommissioning & commissioning of Split AC Units.
Guidelines contained herein shall help the HVAC testing and commissioning team to ensure that the job execution complies with the project requirements and serves the intended function to satisfactory level of the client/consultant.
Overall it is the responsibility of the project manager to make sure the implementation of this procedure.
Precommissioning Procedure for Split A/C Units
Ensure that the indoor and outdoor unit installation is complete and mechanical completion is approved by consultant.
Ensure that no damage has occurred between mechanical completion and precommissioning, if any repair all damages including to the equipment finish paint.
Again check the units are installed as per the approved shop drawings and manufacturer’s instructions.
Check the refrigerant piping installation is complete including all the valves and accessories in line with the approved shop drawings.
Ensure the refrigerant piping network is successfully pressure tested and properly insulated.
All the exposed refrigerant pipes shall be insulated with proper protection as per specification.
Check proper electrical connection between the indoor and out door units / between the outdoor unit and the main power supply.
Ensure that the outdoor units are installed properly and provided with appropriate neoprene pads.
Also make sure that the 1″ dia condensate drain piping installation and insulation is complete.
For condensate drain pipe verify that proper slope is maintained and it is connected to the nearest drain.
Check the wall / slab penetration of the refrigerant piping is properly sealed and water proofed.
Now check that thermostats are fixed and all the relevant wires are connected.
Ensure that the opening around the pipe in the wall/slab are sealed properly with sleeve and approved sealant.
Check that the interface with BMS and Fire alarm system are done.
Ensure the refrigerant pipes exposed inside the room are covered by using PVC trunking / decorative panels.
Commissioning Procedure for Split AC Units
Ensure that all the precommissioning checks are carried out successfully and approval is taken from consultant to commission the system.
The refrigerant piping network shall be subjected to a vacuum pressure of 30″ of Hg.
Open the refrigerant pipe valves of the outdoor unit.
Start the unit and connect the refrigerant cylinder through a manifold to the suction of the compressor and charge the refrigerant circuit.
The charging pressure in the suction & discharge of the circuit depends upon the ambient condition (approximately 60-70 psi in suction & 270-300 psi in discharge).
Refrigerant pressures shall be recorded in the performance record sheet.
Check the indoor and outdoor units are running without any abnormal vibration or noise.
Measure and record the current and voltage of the compressor.
Now measure and record the ON/OFF coil temperature.
Measure and record the total air flow from the unit.
Check the functioning of interface of the unit with BMS and fire alarm system.
Manufacturer’s recommendations for AC testing and commissioning shall be fully followed.
Attachments:
Precommissioning check sheet for Split A/C Units
Commissioning check sheet for Split A/C Units
Performance record for Split A/C Units
Risk Assessment