Garage heater thermostat problems

[GSB Ice Man]

I have had a gas heater in my garage for 5 years. The original mercury thermostat has been kicking the heater on and off and not leaving the unit run till the dialed temp. So, I purchased a new digital battery stat and it worked great for an hour or so. Now it shows LO on the screen and won't kick the heater in. The low temp limit on the stat is 40. I installed new batteries and it turned on for a while then shuts off. Its seams like the stat won't work unless its 40 degrees. I called a heating guy and he got me a heat only stat which worked good for the first 10 minutes but refuses to kick back in. I know the heater stat wires are good because I wire nutted them together to get the heater on. Any suggestions????? Sorry this was so long

[fastkaw]

How do you know it is the thermostat that is keeping the unit from working?

It sounds to me like you have a furnace problem. Do you have the book that

came with it? It will have a trouble shooting latter in it. (home owner use)

I will provably get flamed for this. BUT

Try butting the two low voltage wires together (r+w) the thermostat wires.

and see what happens. The unit should run as long as the wires are together.

If not you have a furnace problem. Get back to us.

DISCLAIMER: i am in no way an expert, at anyting. anything i say is my own opinion and/or observation, and should never be regarded as fact, unless otherwise stated.

[GSB Ice Man]

I used a wire nut and put the wires together, the heater works great. I can't understand how I could be on my 3rd stat.

[MNice]

Get a honeywell T-87, the old round t-stat. 99.9% trouble free IMHO.

[GSB Ice Man]

I installed a T-87 and it worked for ten minutes and refuses to turn the furnace back on. I even disconnected the wires and hooked them back up, and no luck. I am going to get a new stat from the distributor today, I hope this next one works more than once.

[fastkaw]

Most dig. thermostats have a switch in them for the type of fuel you are using,

Is yours set to gas? If so, I think with with this extreme cold, it,s discharging the

batteries. Double AA don't hold up well in the cold. That would account your 1hr.

run time. (partly personal I hate dig. thermostat)

Try to find a mechanical thermostat. There cheep, less then $20 bucks.

Do you still have the first mercury stat? put it back on. Make sure it is level

(very important) If you furnace has a standing pilot set the heat anticipator

at .4 If it has spark ignition set it at .6 Let us know how it works.

DISCLAIMER: i am in no way an expert, at anyting. anything i say is my own opinion and/or observation, and should never be regarded as fact, unless otherwise stated.

[sparcebag]

Please post back crappie commando!

I have the same problem with my propane wall heater in my garage.It at first worked fine then quit like yours!

I just left it after 3 stats,I manually control mine when i use the garage now

[fastkaw]

Crappie commando

Have you checked the voltage at the transformer? 24v or at the r+w wires.

I should have asked first this first.

Some unit heaters/wall heaters use a powerpile system if this is so you need

a powerpile thermostat.

sparcebag

Have you checked this?

[Surface Tension]

It sounds like to me you have something going on with the furnace. I guess I should back up and ask, is this a furnace?

As said your owners manual will have a troubleshooting section that will go through all the steps in sequence of its full operation. Somewhere in that sequence your having a failure, its at that point your manual will tell you what the problem is.

This could be anything from a dirty filter, dirty or loose connection to switches, a rotted hose or air leak to one of the vacuum switches, a plugged or restricted outside combustion air intake, trapped moisture in one of the hoses that froze, and on and on. So find the manual, if you can't find it you might be able to download it off the net. You'll start out by resetting the furnace by shutting the power off to the furnace and turning it back on. You furnace will go though its sequences, if one of those fail revert your manual, the answer will be right there.

[GSB Ice Man]

I called a heating guy who I ordered the 1st stat thru. His question to me was "does it run when the white and red wires are touched together?" I told him it runs like a dream. His answer was that the stat was more than likely bad. I hope this next stat is the answer, otherwise the heating guys will have to stop by and look at it. Oh, there was a switch on the back of the stat indicateing which heater type, and I did have it on my setting(gas furnace).

[sparcebag]

Crappie commando

Have you checked the voltage at the transformer? 24v or at the r+w wires.

I should have asked first this first.

Some unit heaters/wall heaters use a powerpile system if this is so you need

a powerpile thermostat.

sparcebag

Have you checked this?

No I havent fast, I know little about the electrical in heaters! Is that the thing that looks like a transformer?

The R & w wires at stat spark tho.And the heater works manually without the R & W wires crossed

[fastkaw]

sparebag:

Yep the transformer. check the voltage at the R+W thermostat wires, You should

have 24 volts +/- a couple If you don't you need a new trans.

If you only have 20v or less with a thermostat in the system there will be to much

load an the trans and it will not work.

Also have you tried a mechanical thermostat?/not a dig. one

DISCLAIMER: i am in no way an expert, at anyting. anything i say is my own opinion and/or observation, and should never be regarded as fact, unless otherwise stated.

[Ryan Berger]

Go to your local LP supply company and get a millivolt t-stat.. thats what we use when we install garage furnaces..

[sparcebag]

I'll check it Mon.I'll be out there as its warmer fire burnin of course.

I never used a dig.Stat.Got a few Mercury layin around.

[fastkaw]

The old mercury Tstats are the best. (my opinion)

Just make sure they are level any you set the heat anticipator.

The tag on the valve should tell you that setting. The tag in the furnace will tell

you if it is a 24 volt system or a millivolt system.

If you have a millivolt system you need a millivolt Tstat.

DISCLAIMER: i am in no way an expert, at anyting. anything i say is my own opinion and/or observation, and should never be regarded as fact, unless otherwise stated.

[sparcebag]

I forgot to say THANKS fast! My heater is probably early 80s. Monday will tell.

[Surface Tension]

OK we have two furnaces/heaters going on in the same thread.

Lets for the sake of clarity at least give the make and model of these units please. If its one thing we've learned here, give a detailed description which in this case should include make and model. Really guys, we've been done this road of ambiguity too many times to not give info that is as easy as make and model.

Now CC you stated you bypassed the T-Stat once and the furnace worked, later you said you bypassed the T-Stat and it didn't work. I can't ignore logic and come to a conclusion you have 3 bad T-Stats. Not when you furnace failed with a T-Stat bypass. If you want to ignore one post in this thread please don't let it be mine. Get your manual out and do as I've suggested.

[GSB Ice Man]

Well,

I put the new thermostat in 3 days ago and it is working great. I guess I had a couple bad stats.

[sparcebag]

Well,

I put the new thermostat in 3 days ago and it is working great. I guess I had a couple bad stats.

Good for you commando! Mine isnt puttin out the 24 Vs I've got bout 10 and it varies.Old heater and its fine for me the way it is.At least I know the problem!

[fastkaw]

C.C. glad to here it.

Sparcebag A 24v transformer is only about $12 bucks

Make sure it is a 24v- 20va if it's heat only. 40va if it's heating and cooling thermT.