Replaced batteries in house thermostat, not working

ezbtr

Commander
Joined
May 1, 2002
Messages
2,954
Have done it before on upstairs thermostat, now it just reads all "8"'s on digital display, is it time for a new one? All wires hooked up ok and downstairs the same and fine - even after battery replacement, Thanks
 

MTboatguy

Fleet Admiral
Joined
Jul 8, 2010
Messages
8,988
Is there a reset button on it, what model is it, how old is it, lots of questions before saying it is time for a new one!
 

gm280

Supreme Mariner
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Jun 26, 2011
Messages
14,585
I would try to remove the battery, and then shut off service to that thermostat and then return power again. That is a way to reset such things hardwired in. The battery is there for normal power outages to keep programs and such in memory. So removing the battery and turning off power could reset the microcontroller and maybe that will restore the display. If not, well time to replace... JMHO!
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
Are you getting 28VAC from the heater? Measure between R and C terminals on the thermostat.
 

Boomyal

Supreme Mariner
Joined
Aug 16, 2003
Messages
12,072
I had this happen recently on a commercial rental unit. By the time I got there every thing was working. According to the tenants, after replacing the battery, the display was showing all the icons. I do not know how it was corrected but it did. It really aggravates me that you need to use batteries in these high priced thermostats. They ought to have a capacitor memory.
 
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