Tech Challenge – January 2012
A pop cooler utilizing R-22 with a TXV metering device (and receiver) has a customer complaint of warm pop. The symptoms at the convenience store confirm warm product and the condensing unit appears to be cycling on the low or high pressure control. What are the “possible causes” with the following measured conditions on this field service check sheet?
Field Service Check Sheet
Compressor Discharge Temp.
|200 deg. F.|
|Condensing Press./Temp.||262 psig / 121 deg. F.|
|Condensing Outlet Temp.||115 deg. F.|
|Condenser Sub cooling||6 deg. F.|
|Condenser Split||46 deg. F.|
|Entering Feed Device Temp.||86 deg. F.|
|Evaporator Press./Temp.||55 psig / 30 deg. F.|
|Evaporator Outlet Temp.||40 deg. F.|
|Evaporator Superheat||10 deg. F.|
|Compressor Inlet Temp.||50 deg. F.|
|Total S. H.||20 Deg. F.|
|Ambient Temp.||75 deg. F.|
|Room/Box Temp.||49 deg. F.|
|Compressor Volts||240 V.|
|Compressor Amp. Draw||Low|
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And The Answer Is…
The possible causes for these conditions would center on a dirty condenser, blocked or re-circulated condenser air flow. These possible causes would cause the high head pressure/temperature and split. The low side is following the high side with higher pressures and the unit is likely cycling on the head pressure control.
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