Update on frozen A/C coil

markiz41

Member
It lives for now! After cleaning the system, I put the gauges on expecting nothing good, but it still had gas in the low side, just a tad short on the pressure. Pumped in about a pound of R22 using superheat and it ran like a champ. The coming days will tell if the fix was worth it, but I'm happy for now. Thanks everyone for sharing your knowledge and happy 4th of July.
 
I'm not in the AC business but I thought an icy AC coil was do to the coolant not being warmed back up before going back through again.
 
Stephen, Temperature of a evaporator coil is directly proportional to the suction pressure. The temp scale is also on pressure gauge. Any temp below 32 will freeze up a coil. Walk in freezers and even your refrigerator have to have temps around or below zero and the coil has to go through a defrost cycle. It ices up. Most today use 134a

R22, If my memory is correct has to be around 65 psi suction to be above 32 degrees. If you google the temperature/pressure scale for any refrigerant you will see what the suction pressure is to keep from freezing the. Cap tube systems as the ambient temp goes up so does the high side pressure, which effects the suction pressure a little.
 
Iced coil evaporator generally means low airflow through the evaporator.

Check filter and look at coils closely to see if they are clogged with household dust and lint.
 
(quoted from post at 01:17:32 07/05/16) Stephen, Temperature of a evaporator coil is directly proportional to the suction pressure. The temp scale is also on pressure gauge. Any temp below 32 will freeze up a coil. Walk in freezers and even your refrigerator have to have temps around or below zero and the coil has to go through a defrost cycle. It ices up. Most today use 134a

R22, If my memory is correct has to be around 65 psi suction to be above 32 degrees. If you google the temperature/pressure scale for any refrigerant you will see what the suction pressure is to keep from freezing the. Cap tube systems as the ambient temp goes up so does the high side pressure, which effects the suction pressure a little.

I still have the gauges hanging on the wall in the shop. If it's important, I can go look up the pressure/vac and related temp for R11 or R22.
 

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