Furnace shutting off

[Budwag]

Good morning,

We have a 2015 Sierra 357 TRIP, we have used the furnace many times in the past, however waking up this morning it was chilly inside and furnace not working. I have checked, propane (tank half full), plugged into 50 amp service (full power), battery (fully charged), inside temp is 12 degrees cooler than what furnace temp is set at. I have taken out fuse for 2 minutes and re-installed , furnace runs 90 seconds and shuts off. I have shut off thermostat and re-started, again runs 90 seconds and shuts off. What else can I try? How do I access furnace? We have had problems with thermostat in past where we have had to reset to run AC, could that be the problem?

We are camping near Prescott AZ, cold front moving in today and temperatures are expected to drop 15 degrees tonight and get windy. If we can get furnace working may need to pack up this evening.

Thanks,
Budwag

[rockfordroo]

Here's the service manual for many Suburbans. Pgs 27/28 have troubleshooting help.

Looking at a pic of your unit on-line, it looks like it's in your bathroom. Go outside and look for you intake/exhaust. It looks like this:


The furnace will be inside at that same location. You'll probably have to open a cabinet, unscrew a panel, or something like that to get to it.

Good luck.

[KyDan]

If you're on 50 amp service you should be using 2 electric heaters and saving LP although
that won't keep the belly warm and if it's below freezing your pipes could be in jeopardy.

Sometimes furnace control boards just go bad. Happened to me.
The flame sensor circuit in the board goes bonkers.
Does your igniter keep clicking after the furnace lights??

When you start the furace-
1st the blower starts to purge the burner.
2nd the gas valve opens and the spark igniter clicks to light the burner.

If the igniter keeps clicking after the burner lights it means it's not detecting the
flame and shutting down.

There are other things that could be wrong but that's my guess.
Good luck!

[Kimber45]

kydan has a good point. I have two inexpensive electric heaters in my unit when I'm not paying the electric. ( I think they were $10 at lowes) My guess would be something blocking the exhaust vent or there is prob a low oxygen sensor that shuts the furnace when oxygen is low? Crack a door or window for a minute?

[rockfordroo]

Originally Posted by Kimber45

kydan has a good point. I have two inexpensive electric heaters in my unit when I'm not paying the electric. ( I think they were $10 at lowes) My guess would be something blocking the exhaust vent or there is prob a low oxygen sensor that shuts the furnace when oxygen is low? Crack a door or window for a minute?

These furnaces don't have low O2 sensors. Combustion air and exhaust are kept out of the TT. Only way to have exhaust air in the unit is a cracked heat exchanger or leaking combustion air/exhaust connection, which is why you have a CO detector.

The only units I'm aware of that have low O2 sensors are catalytic heaters, where the combustion air and exhaust DOES come from/to inside the trailer.

[Budwag]

Thank you the manual helps.

[Budwag]

Thanks for information

[Budwag]

We appreciate everyones comments and suggestions! We will continue to work and try info provided. Have a great weekend!

[Budwag]

Got it working. Found access in pass through storage compartment, took off panel walls. Tried switching main switch on/off on unit a couple of times no success. Then took off ducted panel, found sensor inside and took off both wiring terminals, then pushed back on. Tried unit again and started working properly. Yup, with my big long body stuffed in the compartment it got hot quickly.

Before re-installing panel and walls, turn unit on 3 more times and it worked great. We are staying the night, we will take everyone's advice, by getting space heater, saving furnace owner manual, and using this forum again if another problem comes up.

Budwag

[Kimber45]

Glad you got it fixed and I learned something new. I have a vent free unit at home with a low oxygen sensor. I guess when a unit has a vent/exhaust the low oxygen sensor is not needed.

[Mr. Dan]

Originally Posted by Budwag

Got it working. Found access in pass through storage compartment, took off panel walls. Tried switching main switch on/off on unit a couple of times no success. Then took off ducted panel, found sensor inside and took off both wiring terminals, then pushed back on. Tried unit again and started working properly. Yup, with my big long body stuffed in the compartment it got hot quickly.

Before re-installing panel and walls, turn unit on 3 more times and it worked great. We are staying the night, we will take everyone's advice, by getting space heater, saving furnace owner manual, and using this forum again if another problem comes up.

Budwag

Thanks for reporting back with your resolution. Reporting back gives honor to the time spent by other members attempting to help PLUS this thread may help someone else who has similar issues.