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rth8500

  1. HVAC
    I have old Honeywell thermostat T874/Q674C with heat pump and baseboard heaters trying to wire it to RTH8500. On Q674C base are wires W1 - white W2 - black G - green Rc,Rh - connected together red B not connected O not connected Y2 not connected Y1 - yellow The manual for RTH8500 saying If...
  2. HVAC
    Yet another Honeywell RTH8500 thermostat install Replacing thermostat: old tstat: BDP (Carrier / Bryant) P271-3457 new tstat: Honeywell RTH8500 heat pump old wiring and old tstat terminals: black - C green - G yellow - Y red - R brown - E blue - W2 no wire - F orange - O white - W1 My...
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