LUX DMH110 - User Manual

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.
Model
DMH110
Problem
Resolution
No fan function in heat mode
Move the switch or jumper on the circuit board to its
ELECTRIC position for electric heat.
Fan on continuously
Move Fan switch from ON to Auto
Remove the "G" wire. If fan continues to run, then
either the system is mis-wired, or the problem is in
the system, not the thermostat.
Indicates incorrect room
temperature
Refer to thermostat manual to verify that your set
temperature is what you expect it to be. The set
temperature is always flashing when it is visible.
"SET" is also visible then indicating that it is the set
temperature.
Your thermostat offers a calibration feature. This
feature may be used to adjust the displayed
temperature up to +5F(3C) or -5F(3C) degrees.
What does the SAVE feature
do
The SAVE button allows you to use one button
press to easily decrease the SET temperature in
winter and increase the SET temperature during
summer. Whenever you leave the house, touch the
Save button to put it in Save mode. By default this
will add 5 degrees to your set temperature in
cooling and subtract 5 degrees from your set
temperature in heating. When you return, touch the
Save button again to cancel the “Save” mode and
return your home to your previous SET
temperature.
Heats or cools more than 5
degrees past its displayed set
temperature
Refer to thermostat manual to verify that your set
temperature is what you expect it to be. The set
temperature is always flashing when it is visible.
"SET" is also visible then indicating that it is the set
temperature.
Remove thermostat body from the wall, leave the
back plate in place. Verify that Heating and cooling
switch off within a few minutes.
If the thermostat is battery powered only, replace its
batteries with fresh Duracell® or Energizer®
alkaline batteries.

LUX DMH110 Specifications

General

Brand	LUX
Model	DMH110
Category	Thermostat
Language	English

Summary

Troubleshooting Poor Temperature Regulation

No fan function in heat mode

Troubleshoot lack of fan operation during heating mode for your thermostat.

Fan on continuously

Resolve issues where the thermostat fan runs constantly.

Indicates incorrect room temperature

Address thermostat inaccuracies in displaying the room temperature.

What does the SAVE feature do

Understand the function and operation of the thermostat's SAVE feature.

Heats or cools more than 5 degrees past its displayed set temperature

Troubleshoot thermostat overshoot by more than 5 degrees.

Wiring Information and Troubleshooting

Low voltage system wiring

Guidance for wiring LUX 24VAC electronic thermostats for low voltage systems.

Heat only system wiring

Instructions for wiring a heat-only system with two wires.

Cool only system wiring

Instructions for wiring a cool-only system with two wires.

Three wire system configurations

Wiring for three-wire systems including forced air heat and water systems.

Four wire system configurations

Wiring guidance for four-wire heat-only systems with clock/timer operation.

Heating and cooling system wiring

Wiring for systems controlling both heating and cooling.

Heat pump system wiring

Wiring instructions for single-stage heat pump systems.

Troubleshooting the Display

Display not changing or unreadable

Resolve issues where the thermostat display will not change or is unreadable.

Blank or fading display

Troubleshoot a blank or fading thermostat display by checking batteries and reset.

Word HEAT or COOL not displayed

Address situations where the 'HEAT' or 'COOL' indicators are not visible.

SAVE feature operation

Explanation of how to use the SAVE feature for temperature adjustments.

Low battery or replace indicators

Troubleshoot 'LO BATT' or 'REPLACE' messages by checking batteries.

Incorrect room temperature display

Troubleshoot the display of incorrect room temperature readings.

Temperature scale conversion

Change the displayed temperature scale from Fahrenheit to Celsius or vice versa.

Display shows OL (Out of Limit)

Understand and resolve 'OL' display meaning 'Out of Limit'.

Display will not light

Troubleshoot a thermostat display that will not light up.