Honeywell Deluxe Programmable Multistage Thermostat, #T8624D
Chronotherm IV Plus

I have 2 of above thermostats and have had for about 5 years. It takes no batteries and is directly connected to a 24 volt source.

Have one upstairs and one downstairs.

Have noticed at times that the LCD on BOTH the upstairs and downstairs has gong blank. Never at same time though. LCD may go out on upstairs but not downstairs.

If I re-seat it on wall mount bracket (thermostat flips up and then comes off wall bracket)
Then LCD usually comes back on.


Today it did not come back on for the upstairs unit.

I then took the downstairs Thermo and put on upstairs bracket and it worked.

So it appears that the upstairs thermo is bad, right?

However, I took upstairs thermo and put on downstairs bracket and it came back on...
Strange...

So then I put them back in their respective places and all was fine.

Go figure...

Ideas??

Again like I said if one LCD goes off the other is on. They never go off at same time. So I can rule out the power source.

Thanks so much
Perplexing?

Peter
Charlotte, NC

It sounds like there is a loose connection either in the sub bases or at the furnace. Typically when those stats go bad they just go.