'73 Tradewind - Getting Roasted in here

[utahredrock]

Note: Original furnace a Suburban NT-22 A.

I am a full-timer. My furnace seemed to be working fine, then today I noticed when I turned down the thermostat the furnace just kept going.

Tonight I was getting roasted. It was about 80 degrees in here with the thermostat set at 60. Turning the thermostat to off did nothing either. Not until I shut the gas valve to off did it finally turn off a few minutes later.

Now the temp is beginning to plummet. Overnight low here tonight will be in the low 20s.

Any ideas? I want to keep additional expenses down. I'll be in cold weather for about two more weeks before heading to the SF Bay area, and then south from there for the rest of the winter.

I am parked at my sister's and think I'll break down and go into her house tonight, but need to get this issue fixed.

Thanks.

Jim
The Airstreaming Meteorite Dealer
utahredrock.com

[whitelight]

Jim,

Sounds like the thermostat itself is buggered . . . we had this problem on a 74' Sovereign - the thermostat never tripped the furnace off.

What brand of thermostat do you have?

It seems that there is an adjustment screw on the inside, which you can see if you remove the cover.

Otherwise, you can pick up a new thermostat for not much . . .

[azflycaster]

You need to see if the thermostat is at fault. You can pull off the cover and see if the contacts are opening up. they may be tacked. On my 75 Trade Wind I can disconnect the wires in the closet in the bath as well. The furnace should run for a few minutes after the contacts are opened. This is to cool down the fire area after the flame as shuts off.

[markdoane]

If you replace the thermostat, be sure you get an electonic one, not one of the ones with a mercury switch.

[crowbar68]

a mercury switch doesn't require electricity if your boondocking.

[utahredrock]

Tempermental Thing

In the light of day I took the cover off and for the first time in my life looked inside a thermostat. When I first fired back up it seemed to turn off fine when I went below the current temp. Now it makes a nice click, the little mechanism switches back to the left, and the furnance just keeps on going.

It's a Suburban thermostat.

[utahredrock]

After about 5 minutes it's switched itself off . . . could have been the cool down phase someone above described. Last night it never shut off at all--till I finally cut the gas to it and even then the fan went on.

[azflycaster]

5 minutes seems about right for the box to cool down. At this point it seems to be working correctly. Things that are working are always the hardest to fix. If it happens again, I would take a look at the thermostat and see it the leer did not click open like it is doing now.

How cold is it getting up in Sedona at night?

[utahredrock]

Thanks for the pointers.

[Lumatic]

Are you aware this furnace was recalled years ago? The problem is with the crossover tube which is a rubber tube about 2" diameter which connects the combustion chamber with the blower. This tube is prone to deterioration which can then pump CO into the coach and can kill you. A lot of parts are no longer available. Other streamers have used radiator hose or gas tank hose to replace this part. You also may have a lot of trouble getting a tech to service this furnace for liability reasons. Many owners have replaced this outdated furnace with newer ones for safety and efficiency reasons. There are posts on this subject in the archives.