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» Support LHP750

Wiring Information and Troubleshooting
  • This page provides general guidance for wiring your LUX 24VAC mechanical thermostat. For more detailed information please refer to the instructions that came with your thermostat..
  • Please make specific note regarding LOW VOLTAGE and LINE VOLTAGE directions. Do not install LINE VOLTAGE wires to a LOW VOLTAGE control. Improper installation of a "C" wire may cause damage to your system.
  • Do no install a wire labeled "TC" from the previous thermostat to any of our controls. Installation of a "TC" wire may cause damage to your system.
  • Do NOT wire by color of the wire, wire by the LETTER designation to which the wire was attached on the previous control.
  • If there were no letter designations on your old thermostat, contact our Technical Assistance Department for assistance.
  • The instruction manual for this model can be viewed in PDF format by clicking here.

Model LHP750
   
Problem Resolution
ALL Never connect a low voltage thermostat to line voltage.
Four LOW VOLTAGE wires for a single stage heat pump R connects to the 24VAC transformer. Connect the heat pump wire to Y, and the fan wire to G.  Connect the reversing valve wire that was connected to B or O to the same letter on new thermostat.  Either O or B will be used, NOT both.
Five wires control a Heat Pump with an auxiliary heat stage. They were labeled: G, Y, R or RH or RC, and W or W2. Either B or O was used Do not connect wires to both B and O. Connect the reversing valve wire to B or O, just as the previous thermostat. Connect  24 VAC wire to R. Connect compressor wire to Y, fan wire to G, and auxiliary heat wire to W2. Add jumper from W2 to E. It is necessary to connect a common wire to the X terminal for heat anticipation and the LEDs to operate.
Six wires control a Heat Pump with an auxiliary heat stage. They were labeled: G, Y, R or RH or RC, and W or W2. Either B or O was used. And Emergency wire E is  present Do not connect wires to both B and O. Connect the reversing valve wire to B or O, just as the previous thermostat. Connect  24 VAC wire to R. Connect compressor wire to Y and fan wire to G. Connect Emergency Heat wire E. It is necessary to connect a common wire to the X terminal for heat anticipation and the LEDs to operate.
For further assistance: Contact your HVAC service company or our Technical Assistance Line if not resolved.
 
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