Acid in System

[redelburg]

Can anyone tell me how the acid is generated or what causes the creation of acid in a system or compressor? I have a theory on why our plastic evaporator drain pans are cracking and the material becoming brittle in our units. It has to do with system leaks and exposure to an acid in the system which comes in contact with the plastic when a system component is replaced or the system has a leak.

[Thermatech]

Check what oil the refrigerant systems is using

Plastic made with mineral oil content & exposure to mineral refrigerant oil = ok
Plastic made with mineral oil content & exposure to synthetic oil = damage to plastic & plastic component failure.

Some plastics which were ok with exposure to Refrigerant R22 with mineral oil are now a problem if exposed to R407c / R410a due to the synthetic oil.

Hopefully someone with chemical degree can explain better.

[Tesla]

For the causes of acid in system and not the breakdown of plastic. From memory acid is caused by moisture in system and high temp. With high temp there are two acids formed and one of the acids create water, can't remember the names of the acids though.

[US Iceman]

Acid formation in refrigeration systems is usually the result of water combining with the refrigerant. When the moisture is compressed to higher pressures, the gas temperature also increases. After repeated cycles the acid begins to form and circulate with the oil. Then the oil carries the acid back to the compressor where it starts to break down the motor insulation (hermetic and semi-hermetic only) or the acid begins to dissolve varies metals (like copper), which then begins to plat other surfaces with the free copper floating around.

I kind of doubt the drain pans are leaking from acid created in the refrigeration system. If you had that severe of an acid problem you have bigger issues than drain pans!

[NoNickName]

Water also help de-esterification of POE oil into its original constituents, which are basicly organic acids like palmitic acid and similar.
Infact, esterification is a process of reaction between one organic acid and one alcohol.

http://upload.wikimedia.org/wikipedia/commons/6/6e/Esterification.png

[redelburg]

Acid formation in refrigeration systems is usually the result of water combining with the refrigerant. When the moisture is compressed to higher pressures, the gas temperature also increases. After repeated cycles the acid begins to form and circulate with the oil. Then the oil carries the acid back to the compressor where it starts to break down the motor insulation (hermetic and semi-hermetic only) or the acid begins to dissolve varies metals (like copper), which then begins to plat other surfaces with the free copper floating around.

I kind of doubt the drain pans are leaking from acid created in the refrigeration system. If you had that severe of an acid problem you have bigger issues than drain pans!

Thanks for the information. It may be a combination of the acids and the refrigerants which are causing the cracking. We did run a test with the plastic material sumerged in POE oil for several days and there appeared to be no affect to the plastic.