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Tech Challenge – September 2018


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A medium temperature cooler utilizing R-134a with a capillary tube feed device has a customer complaint of warm beer. The symptoms at the convenience store confirm inadequate cooling and the compressor appears to be short cycling on the high or low pressure control. What are the “possible causes” (Note: There is only one problem intended) with the following measured/calculated conditions on this field service check sheet?

Field Service Check Sheet

Compressor Discharge Temp. 210 deg. F
Condensing Press./Temp. 108 psig / 92 deg. F.
Condensing Outlet 76 deg. F.
Condenser Sub cooling 16 deg. F.
Condenser Split 17 deg. F.
Entering Feed Device Temp. 44 deg. F.
Evaporator Press./Temp. 5 psig / -3 deg. F.
Evaporator Outlet Temp. 37 deg. F.
Evaporator Superheat 40 deg. F.
Compressor Inlet Temp. 68 deg. F.
Total S. H. 71 deg. F.
Ambient Temp. 75 deg. F.
Room/Box Temp.34 50 deg. F
Compressor Volts 240 V.
Compressor Amp. Draw Low

Looking for the Answer: Check hvac-blog.acca.org on October 31, 2018, for the answer to this issue’s Tech Challenge.


Posted In: ACCA Now, Tech Challenge

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