July 2016 Tech Challenge


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A residential split heat pump system, in the cooling mode @ 86° F. outdoor ambient, utilizing R-410A, has a customer complaint of no cooling. The system has TXV metering device’s on the indoor and outdoor coils with check valves. The symptoms at the home confirm that the compressor and indoor blower are running continually. What are the “possible causes” (note: there is only one problem intended) with the following measured conditions on this field service check sheet?

Note: Cooling Mode. Condenser = Outdoor Coil Evaporator = Indoor Coil

Field Service Check Sheet

Compressor Discharge Temp. 112 deg. F.
Condensing Press./Temp. 295 psig / 94 deg. F.
Condensing Outlet Temp. 88 deg. F.
Condenser Sub cooling  6 deg. F.
Condenser Split 8 deg. F.
Entering Feed Device Temp. 87 deg. F.
Evaporator Press./Temp. 101 psig / 32 deg. F.
Evaporator Outlet Temp. 36 deg. F.
Evaporator Superheat 4 deg. F.
Compressor Inlet Temp. 48 deg. F.
Total S. H. 40 Deg. F.
Ambient Temp. 8 deg. F.
Room/Box Temp. 86 deg. F
Compressor Volts 240 V.
Compressor Amp. Draw Low

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


Posted In: ACCA Now, Tech Challenge

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