September 2014 Tech Challenge


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A Reach-in Ice Cream Freezer designed to operate at -15 degrees and utilizing R-404A with a liquid receiver and TXV metering device has a customer complaint of “warm product.” The symptoms at the convenience store confirm that soft product of 0 deg. F. and the condensing unit and blower are running continuously. What are the “possible causes” with the following measured conditions on this field service check sheet?

Field Service Check Sheet

Compressor Discharge Temp. 230 deg. F.
Condensing Press./Temp. 198 psig / 88 deg. F.
Condensing Outlet Temp. 76 deg. F.
Condenser Sub cooling 12 deg. F.
Condenser Split 13 deg. F.
Entering Feed Device Temp. 77 deg. F. Read just ahead of going into the freezer
Evaporator Press./Temp. 7 psig / -35 deg. F.
Evaporator Outlet Temp. 5 deg. F.
Evaporator Superheat 40 deg. F.
Compressor Inlet Temp. 62 deg. F.
Total S. H. 97 Deg. F.
Ambient Temp. 75 deg. F.
Room/Box Temp. 0 deg. F.
Compressor Volts 240 V.
Compressor Amp. Draw Low

Looking for the answer? Check hvac-blog.acca.org on November 3, 2014 for the answer to this issue’s Tech Challenge.


Posted In: ACCA Now, Tech Challenge

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