Tech Challenge – May 2018
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A commercial split heat pump system, in the cooling mode at 88° 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 continuously. What are the “possible causes” (note: there is only one problem intended) with the following measured conditions on this field service check sheet? Note that in the cooling mode, the condenser is the outdoor coil and the evaporator is the indoor coil.
Field Service Check Sheet
| Compressor Discharge Temp. | 109 deg. F. |
| Condensing Press./Temp. | 295 psig / 94 deg. F. |
| Condensing Outlet | 90 deg. F. |
| Condenser Sub cooling | 4 deg. F. |
| Condenser Split | 6 deg. F. |
| Entering Feed Device Temp. | 88 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. | 8 deg. F. |
| Ambient Temp. | 88 deg. F. |
| Room/Box Temp.34 | 80 deg. F |
| Compressor Volts | 240 V. |
| Compressor Amp. Draw | Low |
Posted In: ACCA Now, Tech Challenge
