A rooftop utilizing R-410A with a TXV feed device has a customer complaint of insufficient cooling.The symptoms confirm inadequate cooling and the compressor appears to be short cycling. 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. 249 deg. F.
Condensing Press./Temp. 444 psig / 125deg. F.
Condensing Outlet Temp. 90 deg. F.
Condenser Sub cooling 35 deg. F.
Condenser Split 37 deg. F.
Entering Feed Device Temp. 90 deg. F.
Evaporator Press./Temp. 157 psig / 55deg. F.
Evaporator Outlet Temp. 68 deg. F.
Evaporator Superheat 13 deg. F.
Compressor Inlet Temp. 73 deg.F.
Total S. H. 18 Deg. F.
Ambient Temp. 88 deg. F.
Room/Box Temp. 78 deg. F.
Compressor Volts 240 V.
Compressor Amp. Draw High