Author Topic: Rheem heat pump  (Read 3869 times)

Offline brya78

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Rheem heat pump
« on: December 12, 2009, 10:02:09 AM »
Hi ,been having problems with my heat pump, at first I had low voltage 20v , replaced transformer , coil still ot pulling in , pump works when I would push contacts manually , however 24v not pulling coil in , replacted contactor , same problem ,checked voltage at thermostat, voltage ok , getting frustrated with it and would hire a pro if i could afford it , but , at this time best to TRY and do it myself , I am a technician in the petroleum c-store industry and am familiar with trouble shooting and dealing with high voltage , just not an HVAC tech and not familiar with the boards , where my signal volts actually come from etc  , my thermostat is a rheem mercury switch unit is 1995 model

Offline Admin

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Re: Rheem heat pump
« Reply #1 on: December 12, 2009, 02:54:34 PM »
The transformer will send 24V to the thermostat on the 'R' wire.  When there is a call for heat, the thermostat will send 24V to the outdoor unit on the 'Y' wire , and send 24V to energize the reversing valve on the 'O' wire .  The 'Y' wire powers the contactor coil and should pull in the contactor.  The 'Y' wire is wired in series with low and high pressure switches that may have tripped.  There's usually a button you have to manually reset.  You'd need guages to check the pressures after you reset the switch.  You could have restricted air flow inside, (dirty filter or coil), or a refrigerant problem, if your dealing with a low pressure lockout.  Some units have the automatic reset, some have the manual reset low pressure switch.  Do you have a model #?