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» Support TX500U

Wiring Information and Troubleshooting
  • This page provides general guidance for wiring your LUX 24VAC electronic 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 TX500U
   
Problem Resolution
ALL Never connect a low voltage thermostat to line voltage.
If unsure how to connect your current wires Contact our Technical Assistance Line or your HVAC service company.
Two wires control a heat only system Connect one wire to W1 and the other to RH leaving in the factory installed jumper wire between RH and RC.
Two wires control a cool only system Connect one wire to RC leaving in the factory installed jumper wire between RH and RC and the other to Y. 
Two wires control heating AND cooling. Currently no Lux controls are compatible with this system.
Three wires for forced air heat only system, where the previous thermostat did not have a clock or timer The previous RH or RC wire is the 24-volt transformer wire. Connect it to RH. Leave jumper connecting RH to RC. Connect the forced air heat system to W1, and the fan wire to G. 
Three wires for a heat only, forced water system that did NOT have a clock or timer This system has a 3 wire zone valve. Connect the 24-volt power wire (usually R or RH) to RH and leave the factory installed jumper wire connecting RH to RC in place, the "valve close" wire to the A terminal and the "valve open" wire to the W1 terminal. The A terminal is powered on at all times when heat is not on.
Three wires control heating and cooling. One wire operates heat, one operates cooling and the third provides 24 VAC Connect the 24-volt power wire to RH. Install a jumper connecting RH to RC. This jumper is usually pre-wired. Connect the heat wire to W1, and the cooling wire to Y. 
Three wires control a cooling only system. One wire operates the compressor, one operates the fan and the third provides 24 VAC Connect the 24-volt power wire to RC. Connect the cooling wire to Y and the fan wire to G.
Four wires control a heating and cooling, electric, gas or oil, forced air system that is NOT a heat pump Connect the 24 VAC transformer wire to RH or RC. Install a jumper connecting RH to RC this jumper is often prewired. Connect the heat wire to W1, the cooling wire to Y and the fan wire to G.
Four wires control a Single Stage Heat Pump. They were labeled: G, Y, R or RH or RC, and 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. Install a jumper wire from RH to RC if a jumper wire was not preinstalled. Connect the 24 VAC wire to RH. Install a second jumper wire from W1 to Y. Connect compressor wire to Y and the fan wire to G. Move dip switch #1 located on the back of the thermostat to the ON position. Set the GAS/ELECTRIC switch on the back of the thermostat to the ELECTRIC position.  Once both of these changes have been made be sure to press the HW_RST button.
Six or seven 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 O or B, just as the previous thermostat. Connect  24 VAC wire to RH and leave in the factory supplied jumper wire between RH and RC. Connect compressor wire to Y and fan wire to G. It is not necessary to wire the E or X2 terminal. Connect W or W2 to the W2 terminal and add a jumper wire from W1 to Y. If you have a C (common wire) connect it to the C terminal. Move dip switch #1 located on the back of the thermostat to the ON position. Set the GAS/ELECTRIC switch on the back of the thermostat to the ELECTRIC position.  Once both of these changes have been made be sure to press the HW_RST button.
For further assistance: Contact your HVAC service company or our Technical Assistance Line if not resolved.
 
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