September 2016 Tech Challenge


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An Ice Cream freezer utilizing R-404A with a TXV metering device (and receiver) has a customer complaint of “soft ice cream.” The symptoms at the store confirm that the case is 20 degrees warmer than normal and the condensing unit appears to be cycling on the low pressure control. 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. 92 deg. F.
Condensing Press./Temp. 205 psig / 90 deg. F.
Condensing Outlet Temp. 82 deg. F.
Condenser Sub cooling 8 deg. F.
Condenser Split 15 deg. F.
Entering Feed Device Temp. 77 deg. F.
Evaporator Press./Temp. 29 psig / -4 deg. F.
Evaporator Outlet Temp. -3 deg. F.
Evaporator Superheat 1 deg. F.
Compressor Inlet Temp. 0 deg. F.
Total S. H. 4 Deg. F.
Ambient Temp. 75 deg. F.
Room/Box Temp. 20 deg. F
Compressor Volts 240 V.
Compressor Amp. Draw Normal

Looking for the answer? Check hvac-blog.acca.org on October 31, 2016 for the answer to this issue’s Tech Challenge.


Posted In: ACCA Now, Tech Challenge

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