July 2015 Tech Challenge


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A freezer utilizing R-22 with a TXV metering device (and receiver) has a customer complaint of “warm case.” The symptoms at the store confirm that the case which normally operates at 0 degrees is at 32 degrees, and the condensing unit is running continuously. What are the possible causes (there is only one problem intended) with the following measured conditions on this field service check sheet?

Field Service Check Sheet

Compressor Discharge Temp. 238 deg. F.
Condensing Press./Temp. 168 psig / 90 deg. F.
Condensing Outlet Temp. 87 deg. F.
Condenser Sub cooling 3 deg. F.
Condenser Split 5 deg. F.
Entering Feed Device Temp. 86 deg. F.
Evaporator Press./Temp. 35 psig / 12 deg. F.
Evaporator Outlet Temp. 32 deg. F.
Evaporator Superheat 20 deg. F.
Compressor Inlet Temp. 54 deg. F.
Total S. H. 42 Deg. F.
Ambient Temp. 85 deg. F.
Room/Box Temp. 32 deg. F
Compressor Volts 240 V.
Compressor Amp. Draw Low

Looking for the answer? Check hvac-blog.acca.org on August 27, 2015 for the answer to this issue’s Tech Challenge.


Posted In: ACCA Now, Tech Challenge

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