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Tech Challenge – July 2021

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An installed split A/C system utilizing R-410A with a fixed orifice metering device has a customer complaint of “insufficient cooling.” The symptoms confirm that the thermostat is not satisfied and the condensing unit and blower are running continuously. The system has only had maintenance and no service calls. What are the “possible causes” (there is only one problem intended) with the following measured conditions on this field service check sheet? 

Field Service Check Sheet 

  • Compressor Discharge Temp.       230 deg. F. 
  • Condensing Press./Temp.              295 psig / 95 deg. F. 
  • Condensing Outlet Temp.              87 deg. F. 
  • Condenser Sub cooling                   8 deg. F. 
  • Condenser Split                                6 deg. F. 
  • Entering Feed Device Temp.          86 deg. F. 
  • Evaporator Press./Temp.               145 psig / 51 deg. F. 
  • Evaporator Outlet Temp.               65 deg. F. 
  • Evaporator Superheat                    14 deg. F. 
  • Compressor Inlet Temp.                 76 deg. F. 
  • Total S. H.                                          25 deg. F. 
  • Ambient Temp.                                 89 deg. F. 
  • Room/Box Temp.                             80 deg. F. 
  • Compressor Volts                            240 V. 
  • Compressor Amp. Draw                 Low 


Check back on August 30 for the answer to this issue’s Tech Challenge.

Posted In: ACCA Now, Tech Challenge

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