Heater not coming back on

Hi, I have a problem that has stumped me and I can't find a good previously posted thread about it.
My house has forced air heating and a run of the mill, standard round mercury thermostat. At the beginning of the day when I wake up, the temp will be really low in the house (I have seen it drop to below 50 degrees). I then turn the thermostat all the way down to 0, then back up to 70. The forced air furnace then switches on and starts to heat up the place. It stops when it gets to about 70 and then it shuts off again until I manually "reset" it.
Any ideas?
-Cold in Montana
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bad thermostat
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Thanks, I will pick up a new one. I have always wanted one of those fancy programable ones anyways.
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I doubt it is the thermostat, which is just a temperature controlled switch. Sounds like a circuit board is getting a safety lockout. You will probably need to get a service tech to check it out. But go ahead and try changing the thermostat first. If it turns out you need a tech, put the old tstat back on, so he will only have one problem to troubleshoot. Make sure you write down a wiring diagram showing the original wiring.
Stretch
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If turning the thermostat all the way down and back up makes its work (with the old simple thermostat), I would agree that it is probably a thermostat problem.
Bob
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Go on, get ya one, but its not your problem.
You have a board going into a soft lockout.
You need to find out why.
99% of the time, its NOT the thermostat. The thermostat has already proved to you it works, and works fine.. its nothing but an ON-OFF switch....period.

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wrote:

loaded super-duper thermostat. A new thermostat usually fixes everything ;-) Everyone knows that :-) Bubba
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Well hell..if thats the case, I got this really nice, PC controlled deal, that will also call, page, and even FAX you when the unit starts to get a problem. It can also call, page, or fax the contractor of your choice to let him know your units about to take a big dump on you. Hey..its wireless too if you want it to be, and even comes with a really nice new Honeywell stat.
Think that $1500 setup will cure the fact hes prob got a 90%+ unit thats got a clogged drain on it?
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No but I will be happy once I recieve faxes at the office informing me that my furnice is on fire. And then the clogged drain isn't so bad.....
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CBHVAC wrote:

No but I will be so happy recieving faxes that it won't matter.
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Toggle Switch........<G>
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Yeah, but it's sticking. I'd take it apart and clean it, myself, just to see if that made any difference.
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LOL..that is funny...you know what happens when they do that....then they want the calibration instructions....
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Yea do you have those instructions CBHVAC? Maybe you cound come out to my house in MT for a looksie?
Oh I fixed this by the way. NOT A PROBLEM WITH THE THERMOSTAT. So that camp was wrong on this thread. It was the board. I jiggled some wires and now it circulates and heats as it should. Great unit. Very happy with it.
But if someone has the calibration instructions and wants to help me with this over the phone... that would be great. I could give you a cookie.
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God no...do 100 of them and who needs an instruction sheet? But, you have to have a wrench that Honeywell will be glad to sell you for about $5, that may, or may not come with an instruction sheet.
its simple..you take a temp reading, if the thermostat is correct, you check level on it and then, if thats good, you dont have an issue. If the stats wrong, you put the wrench on the springs c clamp and calibrate it to the correct temp, level stat and your done.

Hint.. Jigglin wires normally aint a fix...find out WHY you had a bad connection and where. Grounds are notorious for going bad on those and if you have one fail at the wrong time..

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wrote:

I never understood that. I don't give a damn what numbers are showing on the dial. I turn it up until I'm comfortable, and then stop. If I have to crank it up until it says 83 degrees, that's fine by me. If I want to know what the temperature actually *IS*, I'll look at a thermometer.
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wrote:

See? It's almost always the thermostat. Change the stat and THEN get to the problem. I never argue with a customer. They can have whatever they want. :-) Bubba
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We switched to programmable a few year ago and wondered why we waited. Brand name rep suggested Sears as source and ignore their logo on it so I took a DEEP breath and went into their store and got it. Don't remember the brand. Maybe White Rogers?
On 12 Dec 2005 16:02:57 -0800, snipped-for-privacy@gmail.com wrote:

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Instead of turning the thermostat down when it seems stuck, try turning it UP. If the furnace comes on, THEN you will know it is a stuck thermostat.
If turning it down and then back up is the ONLY way to make it come on, then others are right when they say you have a board problem (or a soft lockout). In that case turning it down and then back up sends an OFF signal followed by an ON signal to the furnace, and that resets the furnace controller. --Phil
snipped-for-privacy@gmail.com wrote:

--
Phil Munro Dept of Electrical & Computer Engin
mailto: snipped-for-privacy@cc.ysu.edu Youngstown State University
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