When you are working on an HVAC system and you find you must make refrigerant piping or component repairs, proper system evacuation is absolutely necessary. Once you have opened the system to outside air, moisture begins to enter.
Moisture that enters the system can cause many and serious problems, such as moisture freezing in the refrigerant control orifice, acid, and oil sludging.
Moisture freezing in the refrigerant flow orifice. This will result in poor cooling and lower than normal suction pressure if the orifice is partially blocked. It can also completely plug the orifice causing very high discharge pressure and very low suction pressure.
Acid forming in the system. Moisture will cause acid to form in the system causing serious damage to the compressor and expansion valve parts. It also deteriorates the insulation of the motor windings in the compressor. In the more advanced stages, compressor motor burnout and repeated compressor motor burnout happens. You will also see that the compressor oil is discolored. This condition can be present without the refrigerant control device freezing.
Sludging the compressor oil. Contaminants in the system, including moisture, will cause the oil to sludge (become thicker). Oil that has sludged does not provide proper lubrication to the system, causing damage to the compressor.
Unfortunately, in residential HVAC systems, only the freezing problem is apparent but not always. The other two problems, acid and sludging will not become apparent until the compressor fails. Once the compressor fails it is an expensive repair and will fail again if the proper steps are not taken to correct the problem. Rarely does a compressor burnout or fail without something causing it to fail.
Regardless of the symptom or problem, replace the the refrigerant driers and check the oil color every 24 hours for a few days. Continue to replace the refrigerant driers until the oil returns to a normal color.
Proper system evacuation is the key to preventing damage due to moisture. In our online HVAC training you will learn proper evacuation techniques and procedure.
by Ron Walker
Moisture that enters the system can cause many and serious problems, such as moisture freezing in the refrigerant control orifice, acid, and oil sludging.
Moisture freezing in the refrigerant flow orifice. This will result in poor cooling and lower than normal suction pressure if the orifice is partially blocked. It can also completely plug the orifice causing very high discharge pressure and very low suction pressure.
Acid forming in the system. Moisture will cause acid to form in the system causing serious damage to the compressor and expansion valve parts. It also deteriorates the insulation of the motor windings in the compressor. In the more advanced stages, compressor motor burnout and repeated compressor motor burnout happens. You will also see that the compressor oil is discolored. This condition can be present without the refrigerant control device freezing.
Sludging the compressor oil. Contaminants in the system, including moisture, will cause the oil to sludge (become thicker). Oil that has sludged does not provide proper lubrication to the system, causing damage to the compressor.
Unfortunately, in residential HVAC systems, only the freezing problem is apparent but not always. The other two problems, acid and sludging will not become apparent until the compressor fails. Once the compressor fails it is an expensive repair and will fail again if the proper steps are not taken to correct the problem. Rarely does a compressor burnout or fail without something causing it to fail.
Regardless of the symptom or problem, replace the the refrigerant driers and check the oil color every 24 hours for a few days. Continue to replace the refrigerant driers until the oil returns to a normal color.
Proper system evacuation is the key to preventing damage due to moisture. In our online HVAC training you will learn proper evacuation techniques and procedure.
by Ron Walker