What Can You Learn From Your A/C Pressure Levels

What Can You Learn From Your A/C Pressure Levels?

It is quite common to face issues with your auto air conditioning system. However, it can be difficult to figure out which component is exactly causing the malfunction. It is always a good idea to check the pressure levels of your A/C unit. An efficiently functioning A/C system should have 30 PSI on the low side and 150 PSI on the high side.

The main problem related to a broken A/C system is that the air coming out of the vents do not produce the desired cooling effect. Enlisted below are the characteristic pressure readings of an A/C compressor that is not blowing enough cold air to cool the cabin.

  • High 50 / Low 50 PSI: The clutch is not engaging properly. You need to check the wiring and run power straight to the compressor.
  • High 100 / Low 100 PSI: The compressor does not engage either due to a burnt coil or a lack of power supply.
  • High 125 / Low 30 PSI: Either there is too much oil in the compressor or the system is not properly charged. One should check the refrigerant level as well.
  • High 150 / Low >10 PSI: There might be a leakage in your system or your expansion valve could be stuck open.
  • High 150 / Low 30 PSI: This indicates the presence of excess water in the system. You need to evacuate the A/C system for half an hour, followed by drying and refilling.
  • High 160 / Low 10 PSI: It is possible that the expansion valve may be clogged, the evaporator is frosted, or the low-pressure piping is faulty. Check the expansion valve, evaporator and piping to locate the origin of the issue. A replacement may also be required in some cases.
  • High 200 / Low 70 PSI: There is some sort of blockage in the system, either at the expansion device or before it.
  • High 225 / Low 80 PSI: Either you have excessive refrigerant in the system or a faulty heat sensitizing tube. If your A/C system does not have an orifice tube, then probably the expansion valve is opened too wide.
  • High 250 / Low 30 PSI: There is air somewhere in the system.
  • High 250 / Low 50 PSI: There is either some problem with the condenser or the system is overcharged. Recharge your system and check the condenser for any sign of blockage.

Somewhere around 150 High PSI and 30 Low PSI are the most ideal readings a unit can have.

Measuring the pressure levels can help you diagnose a wide array of operating problems including undercharging, overcharging and a refrigerant leak. The readings, which are found to be too low on the compressor output or the suction line, may indicate that the compressor has difficulty with developing normal pressure ranges, thus affecting the cooling capacity of the A/C system.

At R & Y A/C Compressors, we carry high-end A/C compressors and condensers, all reasonably priced for excellent value. We have been providing quality car A/C parts and service around the U.S., which are backed by reliable customer service.