Can't find in manual. How do I get the cover off the thermostat in order to change the battery? It's a Honeywell Chronotherm IV Plus.

GoGeisel.com - Honeywell Thermostat Owners Manuals (http://www.gogeisel.com/geiselonline/support/Honeywell_Thermostat_Owners_Manuals.html)

Pull GENTLY on bottom from both sides. It will pop off bottom - then the top is "hanging" on two plastic tabs sticking out of back unit. Swing up and forward and it will come off in your hands. Be careful with it putting it back on. There are about twenty five pins that have to line up on two sides to hit the corresponding holes in the faceplate to make the contacts. It might seem like you're pulling too hard, but just remember to pull ONLY from the bottom on BOTH sides and it will pop off.

I've tried to program my honeywell chronotherm I've plus, but it seems to have a mind of it's own. The temperature seems to change all the time. I can't get the temperature to go down at night unless it is down manually. The only instruction I have is what is on the cover.

My Honeywell chronotherm I've plus shows blinking "filter" on small screen and no heat is coming.

My Honeywell chronotherm iv plus shows blinking "filter" on small screen and no heat is coming.

Change the filter in the air handler.