"Air Comm strives ceaselessly to design and produce products that
provide optimal comfort, safety, reliability and value for our customers." - Keith Steiner


Why do I have no cooling?

There are many reasons why your system may not be cooling properly. Some of the most common include:

  • Temperature knob not in full cold
  • No power supplied to the system
  • Circuit breakers popped
  • The condenser fan is inoperative
  • The expansion valve is clogged or has failed
  • The compressor clutch is not engaging or the pressure switch is preventing current to the drive motor
  • The compressor has a damaged reed valve and no longer creates pressure differential
  • The relay powering the compressor drive motor has failed
  • The system may be over or under serviced (see applicable procedures in your service manual for the proper refrigerant charge)

These are only a few possibilities and many require further investigation to determine the source of the problem. If you require troubleshooting assistance please contact Customer Service

My AC system is cycling, what do I do?

System cycling of the compressor can be caused by a number of malfunctions. Some of the most common include:
An over-serviced system. If there is extra refrigerant present it could increase the system pressure and cause the high range of the system pressure switch to disengage the compressor clutch. This would, in turn, reduce system pressure to an acceptable range. The compressor will re-engage at this lower pressure, but the high level of refrigerant will quickly cause the pressure to rise again resulting in system cycle.
Bypass valve stuck open. If your bypass valve is stuck in the open position, it will continuously raise pressure to the high side of your air conditioning system. This could result in an over pressure condition and cause your system to cycle.
Condenser blower malfunction. If your condenser blower is unable to cool your condenser due to a malfunction it could cause your system pressure to rise. This could result in an over pressure condition and cause your system to cycle.
For further information or troubleshooting assistance please contact ACC Customer Service at (303) 440-4075 or 972-407-1234 or info@aircommcorp.com .

Why is one of my evaporators blowing warm air?

This can sometimes be caused by a blocked evaporator expansion valve. If the debris can be seen in the expansion valve it can sometimes be extracted or flushed out by low pressure compressed nitrogen (100 psi or less). Please refer to your service manual for procedures on reclaiming and servicing your system.
What is my specific charge for my air conditioning system?
Please refer to your specific instructions for continued air worthiness. These documents can be found on the Service Manuals page.

How does the freeze switch work?

The freeze switch takes a temperature reading from your evaporator. Upon a low temperature reading, a signal is sent to the bypass valve and the system takes action to avoid a frozen evaporator condition.

If I change my compressor, do I need to add oil?

All Air Comm Corporation compressors come pre-serviced with between 3.5 oz and 5 oz. of oil. Typically you do not need to add oil when you replace your compressor unless you find oil leaking from the system.

What does the bypass valve do?

Upon a signal from the freeze switch, the bypass valve diverts hot gas and/or liquid refrigerant to the evaporator to avoid a freezing condition.

Can I take static pressure readings?

We do not recommend that you take pressure readings with the system off. Variances in air temperature, pressure and humidity often make these readings difficult to interpret. You should take your system pressure readings with the system running and according to the procedures in your service manual.

What kind of oil does my system use?

All Air Comm Corporation air conditioning systems that use R134a refrigerant should use a 100 viscosity, polyester based refrigerant oil. Please note that polyester and PAG oils are NOT compatible and should never be mixed in your system. Irreparable damage to your air conditioner could result.

How long should I keep my system on a vacuum for?

The vacuum process is an important step to insure your system functions at full capacity and is the first step to check for system leaks. This process removes air and moisture from your system. The general rule of thumb is “the longer the better” but Air Comm Corporation recommends at least 30-45 minutes of vacuum before you service your system.