Air conditioning system commissioning and startup is the process of inspecting a new air conditioning installation, and verifying that the new system is running properly and efficiently.

The inspecting technician will take a look at the ducting (if any), the wiring, and the conduit runs.

He’ll verify that the piping is the right size, and check on the pipe insulation and support. He’ll check how and where the unit was installed, he'll check the anchors and brackets, and he’ll verify that there’s good airflow around the unit.

He’ll check to make sure the fans run in the right direction, the supply voltages are correct, the safeties are properly adjusted, and the thermostat is working correctly.

After the technician has verified that the installation is satisfactory, the next step in the air conditioning system commissioning and startup procedure is to start the unit, finish charging it up if necessary, and then verify that it cools normally and efficiently.

If there is a charging chart on the unit, or charging information in the service literature, he’ll verify that the unit is charged to factory specifications.

If there is no factory charging information, he’ll charge to standard HVACR industry specifications.

He’ll write up an air conditioning system commissioning and startup report, and the owner should get a copy.

The report should include the installation evaluation and the operating characteristics of the system:

• head pressure;

• suction pressure;

• subcooling;

• superheat;

• amp draws of compressor and fan motors;

• temperature rise through the condenser coil;

• temperature drop through the evaporator coil;

• wet bulb and dry bulb temperature readings of the evaporator return and supply air; and

• the cfm of airflow through the supply registers.

This information will be valuable to technicians who work on the unit in the future. It provides a baseline snapshot of how the unit ran when it was new and running normally, and it can help identify future cooling capacity problems more quickly.

Because such information saves technicians time when performing service, it saves both the contractor and the customer money.

Also, some contractors require that a qualified technician must perform an air conditioning system commissioning and startup inspection to qualify the unit for warranty.

Publication date: 04/07/2008