Honeywell TH3110D1008 Troubleshooting

If you have difficulty with your thermostat, please try the following suggestions. Most problems can be corrected quickly and easily.

Display is blank

  • Check circuit breaker and reset if necessary.
  • Make sure power switch at heating & cooling system is on.
  • Make sure furnace door is closed securely.
  • Make sure fresh AA alkaline batteries are correctly installed (see page 4).

Heating or cooling system does not respond

  • Set system switch to Heat (see page 3). Make sure the temperature is set higher than the Inside temperature.
  • Set system switch to Cool (see page 3). Make sure the temperature is set lower than the Inside temperature.
  • Wait 5 minutes for the system to respond.

Temperature settings do not change

Make sure heating and cooling temperatures are set to acceptable ranges:

  • Heat: 40° to 90°F (4.5° to 32°C).
  • Cool: 50° to 99°F (10° to 37°C).

“Cool On” or
“Heat On” is flashing

  • Compressor protection feature is engaged. Wait 5 minutes for the system to restart safely, without damage to the compressor (see page 4).

“Heat On” is not displayed

  • Set the System switch to Heat, and set the temperature level above the current room temperature (see page 3).

“Cool On” is not displayed

  • Set the System switch to Cool, and set the temperature level below the current room temperature (see page 3).

Read More Honeywell TH3110D1008 Owner's Manual on PDF Below