Tech Challenge – May 2014


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A Roof top system utilizing R-22 with a fixed orifice-metering device has a customer complaint of “no cooling.” The symptoms at the customer’s office confirm that the thermostat is not satisfied and the compressor, condenser fan, and blower are running continuously. What are the “possible causes” using the following measured conditions on this field service check sheet?

Field Service Check Sheet

Compressor Discharge Temp. 210 deg. F.
Condensing Press./Temp. 182 psig / 95 deg. F.
Condensing Outlet Temp. 87 deg. F.
Condenser Sub cooling 8 deg. F.
Condenser Split 10 deg. F.
Entering Feed Device Temp. 86 deg. F.
Evaporator Press./Temp. 82 psig / 49 deg. F.
Evaporator Outlet Temp. 65 deg. F.
Evaporator Superheat 16 deg. F.
Compressor Inlet Temp. 78 deg. F.
Total S. H. 27 Deg. F.
Ambient Temp. 85 deg. F.
Room/Box Temp. 80 deg. F.
Compressor Volts 240 V.
Compressor Amp. Draw Low

Share this challenge with your technicians to find out if they can figure out the problem. You can also share your thoughts here by posting them in the comments section below. Check back after September 1, 2014, for the correct solution.


Posted In: ACCA Now, Tech Challenge

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