Has anyone here ever replaced a thermostat?

[Paper Roses]

Something bizarre happened while I was away for 3 days. I keep the temp at 64 degrees in my house.
Came home to a 38 degree kitchen and an 42 degree LR.
The furnace did not kick on while I was gone. When I came home I goosed the dial to 65 degrees and the furnace started right up and has seemed to keep going as always.
Don't know if this was a funny glitch or if I have a problem

It is $125.00 to have the oil company come to check things out.(This does not count the cost of parts or repair) Can't afford it. Can find no reason this should happen. Any ideas?

If it happens again, could it be the thermostat and is it a do it yourself project? I have a 6 year old dial type unit. When the furnace was replaced (6 years ago), they put in a digital unit. It turned on and off every few minutes. Too sensitive, I had them put in one of the older round type and I'd like to keep this dial type if that is the problem.
So far no more bizarre incidents.
Sound like anything familiar?

Could this old lady replace it herself? I have no idea what it involves.

[X_Digger]

1. It involves usually three or four wires, if I recall.

I replaced our older unit a couple of years ago.

All it really took was turning off the breaker controlling the unit, then swapping thermostats.

The instructions that come with the new thermostat will have wiring charts- ie, if your wires are brown, yellow, red, and blue, then connect brown to the screw marked '1', the yellow to the screw marked '2'. If your wire colors are red, black, blue, and brown, then connect red to '1', etc etc etc.

It's definitely DIY-able in most cases.

[NYC_SKP]

2. Usually four wires, color coded, standard.

It's not hard if you take your time.

*** It's advisable to always find the breaker for your system and turn of the power. However, the little wires are low voltage (24 volts) and won't hurt you. But still...

Tip number one, make sure you mark on the old thermostat where each wire goes before you disconnect, they are usually four different colors.

Two, if your phone takes pictures, take a couple pictures.

Three, bring your old unit with you to the hardware store, and your camera phone pictures.

They should be able to tell you anything you need to know.

Bring home the replacement, attach wires as directed.

Good luck!



ETA, there are great videos on youtube, find the right one!

[TreasonousBastard]

3. Before replacing it, it's possible that a piece of grit or...

insect part got in there and stopped it from working. By goosing it you may have dislodged whatever it was and it should work from now on.

If the problem repeats, then you may have to replace it.

[X_Digger]

4. True, but..

.. there are some good energy savings to be had from a thermostat that you can set up to maintain different temperatures during the day, rather than one fixed temperature.

I know that when we installed a new thermostat and programmed it for when we were at work, we saw about a 10-15% drop in our electric usage, year over year.

[Warpy]

6. Old folks at home use their index fingers

I'm home so when I do go out, I turn it down. Same for when I go to bed.

Since I don't have a set schedule, the programmable job would cost me money.

[Kaleva]

13. True. A programmable t-stat isn't for everyone.

[Warpy]

5. I did it a few years ago, only to find out the transformer under the house had fried

I called a poor schmuck in to deal with that since I'm not physically capable these days.

However, the thermostat is easy. It's on a 24 volt circuit, so you don't have to worry about being knocked flat by it, although completing the circuit with a finger will sting. Just unscrew the old one, note how the wires are connected, disconnect it, connect the new one and screw it in. Calibrate it according to the directions on the package if it's a mercury tube job like mine is.

http://home.howstuffworks.com/home-thermostat2.htm

There are instructions on You Tube that will scare you to death because they're all pushing the programmable thermostats, something I'm guessing you don't want any more than I did.

You'll need flat head and Phillips screwdrivers, possibly a drill if the new thermostat screws in differently, and a large vocabulary of foul language.

[Paper Roses]

8. Hi Warpy, have both types of screwdrivers and a good vocabulary. Waiting a few days to see that hap

This is the biggest pain in the pa-toot. Sure as I replace this thing, it will be something else.
By next week, if things are not normal, I will make the plunge.
Geeze, I wish I went to tech school and learned to be a plumber or electrician. My problems would be about half.

[Warpy]

9. I don't know which is worse

my old house falling down or my old body falling down like an old house.

However, the thermostat was a snap.

[Paper Roses]

11. Boy, can I relate to your statement! n/t

[OffWithTheirHeads]

7. What you have is a Honeywell T-87F

The advice you got here is correct. DO turn the breaker off! 24 volts won't hurt you (unless you stick it in your mouth which I learned using my teeth for a wire stripper) but you can fry thr 24 volt transformer if the wrong bare wires touch each other.

[LiberalEsto]

10. Yes. Followed the instructions and it was a piece of cake.

I installed a programmable thermostat a couple of years ago. I'm 61, female, and not particularly handy but I can do minor things.

Remember to switch off the electrical current for the furnace/thermostat while you're working on it.

[Kaleva]

12. The type of thermostat you have can last for 2 or more decades

I've replaced many in the past few years that were installed back in the 60's & 70's and the only reason they got replaced was that the homeowner was upgrading his heating system.

If you have an old style mercury bulb thermostat, they generally don't "glitch" but can be affected by a dust buildup on the bulb and insides. If you can remove the round cover, gently blow on it and use a Q-tip to gently wipe off the dust off the bulb, if there is any left after blowing on it. Turn off the power to your heating system before doing this.

Back when I did service work, I kept a sandwich bag of Q-tips in the work van for cleaning mercury bulb t-stats and for wiping clean cad cell eyes.

[Paper Roses]

14. Thanks for your cleaning tip.

This thermostat is only 7 years old and I believe it is one of the mercury type. The no-heat event happened only the one time I posted about it but I will still see if I can get the cover off to check the dust situation.

I can throw the main(red) emergency switch to shut off the power for a few minutes....I think.
I don't know any other way to cut the power and do not want to mess with the circuit breakers.

Blizzard due here next two days, think I'll try it this afternoon.

[Paper Roses]

15. Hope I am not in trouble. This AM, the first floor was 55 when I got up.

The Thermostat was set at 64. Got brave enough to pull the cap off the unit(round Honeywell). The inside is not like the old mercury one we had. It is circuits.
I blew some compressed air in the back of the face unit and on the wall mounted part.
I had flipped the emergency switch off.. I touched the prongs gently with a q-tip and reattached the face part.
Jacked up the heat to 70 and it is now running. I am trying to get the heat up to a civil level.

I don't know if this little chore did anything and if I need the fuel company to come. Big $$ and right in the middle of a blizzard.

I just went to check and it is still going. Something I never noticed, there is a little light bulb(?) shaped icon showing on the left side of the dial. Don't know what it is and I have no paperwork to check. It was installed with the new furnace 7 years ago and nothing was left for me to refer to. I turned the dial just a little, bulb disappeared and then came back. Since I never had occasion to fiddle with the thermostat before, maybe this was always there and just shows that the furnace is on.

Talked to fuel company this AM and told him what I did, he suggested that I just watch it now that it is running...maybe it was just dust.

They will come for a service call even if we get a ton of snow. I'm keeping my fingers crossed.

[Kaleva]

16. If it happens again, I think the t-stat needs to be replaced.

There apparently is nothing wrong with the new furnace so you ought to have heat during the blizzard even if you have to turn up the setting on the thermostat to turn the furnace on.

I believe that light bulb icon you see is just an indicator letting you know there is a call for heat.

Here is a link to an owners manual pdf file for the thermostat you may have.

https://customer.honeywell.com/resources/techlit/TechLitDocuments/69-0000s/69-1679EF.pdf