Is my house thermostat broken?

[Paper Roses]

My furnace and thermostat are 7 years old. Oil heat.
Four days ago, it was so cold I had to turn on the furnace. This was the first use this year. The thermostat is a round digital unit made by Honeywell. No model # visible on the outside. Shows temp in room on the dial. I have it set at 63 degrees.

Yesterday the furnace should not have triggered on. It was 70 degrees inside and outside. It would turn off eventually but came on again and again. Still 70 degrees in the room. This happened several times. I finally threw the main furnace switch to stop this waste.

I can go to the fuel company and ask them but I know they will say I have to have the furnace cleaned or have them come at a minimum of $100.00 to check and replace. I have it cleaned every year but was going to pass this year. Lack of extra funds. If the symptoms are of a broken unit, is it a do-it-yourself job to replace the unit?

I have no paperwork on the thermometer to go to the manufacturers site for into and I don't know how to take the cover off.

Any help is appreciated.
PR

[LiberalEsto]

1. Check the batteries!

A few weeks ago I thought either my furnace or thermostat was broken. I called the company that installed the furnace. They sent someone out, and he found that I simply needed to replace the AAA batteries in the thermostat.

So as not to waste the $60 service call, I asked him to inspect and clean the system to get it ready for the heating season.

[Inchworm]

2. I had a round thermostat

And it did go bad. Mine was much older and did not have batteries.

I replaced it fairly cheap with a $20 digital thermostat from Lowes. It was real easy to do. Remove, connect two wires, replace, done.

In hindsight, I wish I'd have gotten a programmable one for $50ish dollars (I didn't have the $$). That way I can lower heat usage at night when I'm supposed to be snuggled up in bed.

:hi:

[Wash. state Desk Jet]

3. It many need to calibrate itself.

Put a cheap thermometer above the thermostat and set your temp at 55 for a few days.your thermostat cannot recalibrate itself if you shut off the power to it.

The weather is not consistent this time of year and neither is your thermostat as a result of it. Should be a 24 volt thermostat right ?

Round the number off to 60 or 55 degrees for the time being . Compare the cheap thermometer reading to the reading on your thermostat.

A new thermostat the same type is about $30.00 . The directions will tell you all you need know to install it if you need a new one . you most likely do not need a new one. Relax it is a common happening this time of year as the cold weather sets in. !

Good luck and don't worry about it !

[amerikat]

4. Do you have hot water baseboard or radiators?

I have hot water radiator heat. My furnace comes on sometimes when the
thermostat is not calling for heat. The furnace guy told
me my furnace had internal controls that turn the furnace on
to maintain a certain level of heat in the system. This is
so that it doesn't take so long to get heat when the thermostat
calls for heat. I turn mine off at the switch. I'm going to have
a new furnace soon and will have that feature disabled.
Hope this helps.

[Paper Roses]

5. I have radiators, flipped the switch again today and it doesn't seem

to turn on like it did yesterday and the day before. Still mild out. I took the cover off the thermostat today to see of it was dusty or needed batteries--something visible. No dust, no battery. I am going tomorrow to my fuel supplier to see if they can tell me what is going on.

[Paper Roses]

7. Thanks for confirmation.

I have hot water/radiators. Yesterday I went to the office of my fuel company to discuss what was happening and they told me just what you said. It is a pain but shortly it will be going on it's own anyway. The few warm days are gone and for my neck of the woods, this is the beginning of the cold weather. In the spring when it gets warm again, I'm going to flip the main switch. I don't want to waste oil and certainly don't care about a few more minutes for the heat to get to my radiators.

Thanks all for your suggestions.

[marybourg]

6. When you take off the cover do you see a small tube filled with

mercury (silver liquid)? If yes, tilt it down on one end. If that starts the furnace, dust off everything gently. If not, it's probably shot. A new programmable can be had for $50. Installation is pretty easy and it keeps the house much more evenly heated than the round Honeywell.