Normal R22 Pressures

R22 is a refrigerant that was phased out in 2010. The newer R-410A is becoming more prevalent and requires technicians to learn how to work with this higher pressure replacement.

One of the first things a technician learns is how to read the pressure and temperature of an air conditioning system. Then, they have to make sure that their tubing is sized properly.

High Side

The high side of normal r22 pressures is the output pressure from the compressor when the refrigerant is at evaporator saturation temperature. This is where the pressure can be higher than the incoming pressure, and varies depending on the refrigerant model and compressor motor size.

This can be a good thing, but if the low side is too high then it can lead to reduced efficiency of the unit or even failure. This is why it’s important to check the high side and low side of your refrigerant at regular intervals.

As a general rule of thumb, the low side of the system should be around 60-80 psig, which is below the output of the compressor during normal operation. However, it can be a little higher than this in cases where the indoor wet bulb temperature is lower and the outdoor air is warmer. This can be caused by a lack of a sufficient heat load to raise the vapor line pressure to the output pressure of the compressor.

Low Side

Normal r22 pressures for an air conditioning system can vary depending on the compressor model, refrigerant used and ambient temperature. For a properly functioning air conditioner, the low-side suction or incoming line pressure should be about 75 psi and the high-side output pressure should be about 260 psi.

For example, with 95 F outdoor temperature and 80 F indoor air temperature the condensing temperature is 125 F (ambient plus 30). Using a refrigerant pressure chart you can see that at this temperature the incoming suction line pressure is about 76 psi and the output high-side compressor pressure is about 260 psi.

The pressures in the system also equalize when the motor is not running. This allows the low-side suction pressure to remain relatively constant so that the temperature on the evaporator coil remains close to its operating temperature.

Compressor Motor

The compressor motor (the cylinder that rotates) compresses the refrigerant gas before it is condensed into a liquid in the cooling coil. The output pressure from the compressor is then used to cool air and recirculate it back into the building.

The normal operating pressures for R-22 vary by ambient room temperature and heat loads. Service manuals provide charging charts that help to determine the target suction vacuum pressure (negative) and output pressure for a given compressor motor.

As with other psig values for refrigerant, the low side pressure varies by ambient temperature. For example, an indoor air conditioning system that uses R-22 refrigerant at 80 degrees minus 40 degrees (evaporating temperature) will produce a refrigerant line psig value of about 75 psi.

Condensing Coil

During the refrigeration process, refrigerant is heated in the compressor and then is cooled by condensing on the coil. This condensation causes the gas to become liquid.

The coil on the outside of your air conditioning unit is prone to being infiltrated by small particles of debris such as twigs and dry leaves. Regular coil cleanings help prevent this from occurring and should not be neglected.

If you are having a problem with your condensing coil, it may be time to replace it. A new coil can cost a lot of money depending on the size and model of your system.

If you are having a problem with your air conditioning system, it is important to have an experienced HVAC technician inspect your system and repair any problems that they find. This will ensure that your system performs properly and efficiently, as well as help to extend the lifespan of the components in your system.