Why is acid such a concern in a refrigeration or air conditioning system?
For a hermetic or semi-hermetic unit, checking for and removing acid is probably the most important maintenance check! The operating life of refrigerators, heat pumps, and air conditioners are severely shortened by acid levels as low as 50 parts per million of acid! These acids can be formed by chemical reactions with components and/or materials of construction, lubricating oils, and/or impurities. The instability of the refrigerant, and thus the formation of acids is accelerated by elevated temperatures which could be the result of improper operation, such as a failed condenser fan, a clogged air flow path, or an improper refrigerant change-over. Acid formation can also be the result of oil and/or refrigerant incompatibilities, such as mineral oil/POE oil incompatibilities, refrigerant/gasket material incompatibility (Viton/R-134a), low thermal stability of the HFC refrigerant/oil mixtures, or extended operation off the design point. Checking the refrigerant and/or oil acid is a commo
