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Troubleshooting Poor Temperature Regulation
• This page lists problems that may affect the temperature performance of your LUX thermostat with suggested resolutions.
• For more detailed information please refer to the instructions that came with your thermostat.
The instruction manual for this model can be viewed in PDF format by clicking here.
 
Model LHP750
   
Problem Resolution
Fan On continuously Move Fan switch from ON to Auto
Remove the "G" wire. If fan continues to run, then either the system is miswired, or the problem is in the system, not the thermostat.
Heats or cools more than 5 degrees past its displayed set temperature Verify that your units placement and mounting are optimum per the installation section of its manual. 
If poor performance is in Heat mode, refer to the installation section of the thermostats  manual to verify that the units anticipator is set appropriately. Note that it may be adjusted  from the recommended setting to accommodate your preferences.
No heat or cooling when expected Refer to wiring to verify that it is according to the wiring diagram for your system.
If your system is a low voltage system having 24VAC or less, and you are technically inclined, you may jump terminals as given below out to detect a malfunction in your system.
No heat anticipation This unit requires a common voltage connected to the X terminal to power heat anticipation. 
Fan Test FAN TEST: Test your system fan first.
With the power ON at the fuse box, touch the "G" wire to the "R" terminal. The fan should come on immediately and stay on. The rush of air is usually easily heard.
If the fan does not come on it is an indication that there is a problem with your system. Check any breaker o fuses that fed the 24VAC transformer that powers your system 
If persists, contact qualified service personnel for aid in determining the fault.
Heat Pump Test To test a heat pump system with an "O" wire, three wires must be connected together with the power terminal. The power terminal is "R". With the power ON at the fuse box, connect the "O"  and "Y", and "G" wires to the "R" terminal for a couple of minutes and the unit should provide cool air. Wait at least 5 minutes and repeat this test without the "O" wire. The unit should provide Heat.  
To test a heat pump system with a "B" wire, three wires must be connected together with the power terminal. The power terminal is "R". With the power ON at the fuse box, connect the "B"  and "Y" and "G" wires to the "R" terminal for a couple of minutes and the unit should provide warm air.  Wait at least 5 minutes and repeat this test without the "B" wire. The unit should provide cool air.  
Thermostat Emergency Heat Test 1. Set unit to EMERG HEAT mode. 
2. Adjust set temperature to at least 5 degrees below room temperature and wait for all equipment componts to shut off.
3. Adjust set temperature to at least 5 degrees above room temperture.
4. With the set temperature raised, confirm that the blower fan is on, and the air coming from the vents is warm.  If air is blowing but feel cool, there is likely a problem with the heating equipment and a service technical will have to inspect the system componts.
Advanced Trouble Shooting If your system is a low voltage system having 24VAC or less, and you are technically inclined, you may jump terminals as given below out to detect a malfunction in your system.
Fan Test FAN TEST: If your system has a fan, test it first.
If the system is Heat only, or if there is a jumper between the "RH" and "RC" terminal of your thermostat, then with the power ON at the fuse box, touch the "G" wire to the "RH" terminal. The fan should come on immediately and stay on. The rush of air is usually easily heard.
If the system is Cool only, or if the system is Heat and Cool and there are separate wires to "RH" and "RC",  and there is no jumper between them: then with the power ON at the fuse box, touch the "G" wire to the "RC" terminal. The fan should come on immediately and stay on.
If the fan does not come on it is an indication that there is a problem with your system. Check any breaker o fuses that fed the 24VAC transformer that powers your system 
If problem persists, contact qualified service personnel for aid in determining the fault.
Heat Pump Test To test a heat pump system with an "O" wire, three wires must be connected together with the power terminal. The power terminal is "R". "RH" and "RC" with a jumper between them my also be consider to be a single "R" terminal. With the power ON at the fuse box, connect the "O"  and "Y" or "Y1" and "G" wires to the "R" terminal for a couple of minutes and the unit should provide cool air. Wait at least 5 minutes and repeat this test without the "O" wire. The unit should provide Heat.
To test a heat pump system with a "B" wire, three wires must be connected together with the power terminal. The power terminal is "R". "RH" and "RC" with a jumper between them my also be consider to be a single "R" terminal. With the power ON at the fuse box, connect the "B"  and "Y" or "Y1" and "G" wires to the "R" terminal for a couple of minutes and the unit should provide warm air.  Wait at least 5 minutes and repeat this test without the "B" wire. The unit should provide cool air.
For further assistance: Contact your HVAC service company or our Technical Assistance Line if not resolved.
 
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