Thermostat (?) Problems With Air Conditioning
I have been experiencing a rather odd air conditioning problem. My thermostat (a Honeywell-round style) has been not turning off my air conditioning at the proper temperature. It will kick on the a/c at any degree I set it, but will continuing running until I have to get up to turn it up again. It will drop the house temperature at least 6 degrees before it will shut off. I have replace the thermostat ( the round part) but not the thermostat base which controls both heating and a/c. The plate is solid state with no moving parts. What could be the problem? The a/c works well and I understand the thermostat is just a fancy switch, turning the unit on/off. I am sure that this is not efficient with the a/c running for at least 3 hours at a time without cycling off. Any suggestions?
Answer:
Sounds like a bad cooling anticipator on the sub-base (the part you didn't replace) For what the T-87 & Q-539 (the thermostat you have) cost, you could buy a pretty decent programmable stat. For a little more, you could buy a really nice one. Either of these options would fix the problem and save you a couple of bucks in the long run. Eric What you've described is *exactly* what our 18-year-old Honeywell thermostat was doing. But, rather than fiddle with it, we just replaced it with one of those programmable jobs--not a real expensive one, but you can enter different times/temps for weekdays, weekends, etc. It has already saved us more than it cost us because we often forgot to set the temp UP on weekdays before. It even reminds us when it's time to change the air filter! I think it's accurate (turns AC or heat pump off or on) within a degree of the setting.