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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a Honeywell thermostat ('t know kind except was

Customer Question

I have a Honeywell thermostat (don't know kind except was installed a year ago with a new Heating/Air Conditioner) and now have one problem with it and it is this:
Possibly I get to hot in the middle of the night, go to change the thermostat and the digital display doesn't light up and do not know what the present temperature is let alone cannot change it since I can't see the digital readout. I had a programmable one but didn't want that so it was exchanged for one which is simpler - just has the digital readout with several buttons to push for FAN-auto/on, SYSTEM-cool/off/heat at the bottom and on the left side is the digital display of the temperature and on the fight side are 2 buttons (one above which has a up display and the one at the bottom with a down display which one presses to raise or lower the current temperature). I thought there might be a battery in it but didn't seem to find any way to open the thermostat up so don't know what is wrong with it. When it does act up, I press various buttons and eventually it lights up again but certainly don't want it not to work and the digital display not show me what the actual temperature is. What is wrong and how can I fix it (if I can)? Delores Moyer, (###) ###-####or***@******.***
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.

Hello Delores,

we need to do a few tests.

Press the up button on the right side, tell me if temp setting goes up or not AND if it lights the display or not.

Then do the same with the down button and tell me if lights the display or not.

If not, turn the System cool/off/heat switch to OFF, then back to heat and tell me if lights the display or not.

Repeat these tests a few times until you get consistent results and know the pattern.

Tell me what you find, we can go from there.

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