March 2019 Tech Challenge


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A rooftop system utilizing R-22 with a fixed orifice has a customer complaint of insufficient cooling.The symptoms confirm the thermostat is not satisfied and the blower and compressor appear to be running all of the time. What are the “possible causes” (Note: There is only one problem intended) with the following measured conditions on this field service check sheet?

Field Service Check Sheet

Compressor Discharge Temp. 241 deg. F
Condensing Press./Temp. 262 psig / 121 deg. F.
Condensing Outlet 98 deg. F.
Condenser Sub cooling 23 deg. F.
Condenser Split 41 deg. F.
Entering Feed Device Temp. 88 deg. F.
Evaporator Press./Temp. 90 psig / 54 deg. F.
Evaporator Outlet Temp. 62 deg. F.
Evaporator Superheat 8 deg. F.
Compressor Inlet Temp. 65 deg. F.
Total S. H. 11 deg. F.
Ambient Temp. 80 deg. F.
Room/Box Temp. 82 deg. F
Compressor Volts 240 V.
Compressor Amp. Draw High

Looking for the answer? Check back on April 30, 2019.


Posted In: ACCA Now, Tech Challenge

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