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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 8767
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a 10 ton Trane unit that hasn't been cooling worth a

Customer Question

I have a 10 ton Trane unit that hasn't been cooling worth a crap for a while. Saturday I pulled the charge out of both compressors and weighed in factory listed charge. upon start up my pressures were reading 95/325. outside air temp about 100. after several minutes the circuit 1 compressor shut down and pressures equalized at about 175. circuit 2 continued running with low side never dropping below 90 and hi never below 325. Any ideas??
JA: Did you double-check the thermostat's settings? And what about the filters? Do you plan on doing the work yourself?
Customer: yea inside was in cool call and filters are new and coils were cleaned last week
JA: Anything else we should know to help you best?
Customer: unit is about 9 years old and cools a restaurant dining area. about 3-4 years ago it did receive some pretty bad hail damage, I have combed out the fins as best that they can be
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.

Hello, IF... this system uses Refrigerant 22 it is way over charged, if it is using R-410a it may not be over charged, the inside of building temperature may be so high, at 100F outside air temp that the compressors are overloading (that can happen at 85 or 90F+ indoor temperatures)

Have you cleaned the condenser coil yet?

Let me know about all that, we can go from there.

Customer: replied 1 year ago.
it is a R-22 system and yes both coils have been cleaned. I removed the charge and weighed the factory charge back in.
Expert:  Phil replied 1 year ago.

Causes of the high head pressure can include:

Condenser fan blades replaced with wrong type or rotation.

Condenser coil has dirt deep between the fins where you can't see it

Air in the system (not using vacuum pump, and other causes)

If you did not evacuate the system before weighing the charge there would have been a pound or more of refrigerant left in the system dissolved in the oil.

You will most likely find that removing refrigerant until you meet the head pressures shown on the chart (for 100F outside air ONLY) the system will resume proper operation.

Look all that over, we can go from there as needed. Please hold your rating until we get the situation resolved