DIYbanter - View Single Post - Carrier Thermostat Clock not keeping time

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George E. Cawthon wrote:
wrote:
I have a carrier programmable thermostat that is approx 3 years old.
The thermostat works fine, but the clock is not keeping time correctly
(losing about 15 minutes a day). There hasn't been any power outages
as none of my other clocks are affected.

I thought there might be a battery somewhere, but I took it off the
wall and don't see one (I believe it is powered by AC). Does anyone
know if there is a battery somewhere or does it probably need to be
replaced?

Thanks

Never heard of a programmable thermostat that
doesn't have a battery. Normally they are powered
by AC but the battery is to remember the program
when the AC power goes off. A low battery could
affect the clock.

A low battery can affect the clock by stopping it or having it reset to
12AM. But the clock keeps time via a crystal oscillator that is
voltage independent. Otherwise, all digital clocks would lose time as
the battery decays, but they don't.

Sounds like this is a defective thermostat