Trouble Shooting from the Display

Problems that may be identified from the display of your programmable thermostat are listed here with suggested resolutions.
 

For more detailed information please refer to the instructions that came with your thermostat.

Those instructions can be viewed in PDF format here.

 

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  FROM THE DISPLAY
Model DMH100
Problem Resolution
Display will not change.
  1. Peel protective plastic label from display.
   
Display blurred and unreadable.
  1. Peel protective plastic label from display.
  2. Press the small round inset RESET button on the front of your unit using a small Philips screw driver.
   
Blank or fading display
  1. Replace thermostat batteries with fresh AA size Duracell® or Energizer® alkaline batteries. Be sure that they are installed with their polarity (+ and -) correct.
  2. Clean battery contacts with a pencil eraser and pry out the spring contact slightly to insure a clean, firm connection.
  3. Press the small round inset RESET button on the front of your unit using a small Philips screw driver.
   
Displays "LO BATT", "REPLACE", or
battery symbol
  1. Replace thermostat batteries with fresh AA size Duracell® or Energizer® alkaline batteries. Be sure that they are installed with their polarity (+ and -) correct.
  2. Clean battery contacts with a pencil eraser and pry out the spring contact slightly to insure a clean, firm connection.
   
Displays wrong room temperature
  1. See Temperature Regulation
   
You want to change the displayed temperature scale from °F to °C or
from °C to °F
  1. A jumper comprised of two small pins on the units circuit board and a black shorting device control the units displayed temperature scale. Place the shorting device over both pins to use the Celsius scale and over only one pin (either one) to use the Fahrenheit scale. Then press RESET using a small Philips screw driver.
   
Shows "888" on display
  1. Reset your thermostat.
   
Shows "OL"
  1. This means Out of Limit. The sensor is reading outside the thermostats display limit. Room temperature will reappear when the temperature returns to switching the range. If actual room temp is not over 95 degrees, there may be a malfunction. Press the HW RESET button on the circuit board to reset.
   
Display will not light
  1. This Lux model thermostat does not have a back light.