Furnace will not shut off

JerryS

Advanced Member
Joined
Oct 26, 2014
Messages
52
We have developed a problem in our 2020 Rockwood Signature 8329SB.

We have the Coleman Mach system with a thermostat that controls 2 Air Conditioners, and the single furnace.

We have a Suburban furnace. Not sure of the model number, but my owners manual is for all the SF-xxQ and SF-xxFQ series models.

We have had family staying in our trailer off and on during the months of November and December. The furnace has worked perfect without issues.

We went on a vacation between Christmas and New Years and the furnace worked without issue.

Once home, we left the furnace on to help with the cold weather we were having, since we had not drained any water lines. So basically, the furnace has worked great for at least 2 months.

Yesterday I went out to the trailer and when I opened the door, I was hit with a blast of really hot air. The thermostat showed it was 78 degrees in the trailer, even though it was set on 58 degrees.

I tried turning it off, and at first I could not get the thermostat to respond to any button presses. Eventually, it did respond, but I could not get the heater to turn off.

I ended up having to pull the fuse for the thermostat and it finally cut off. I waited about an hour and installed the fuse back. The furnace immediately turned on and fired right up, blowing hot air. I pulled the fuse again and left it overnight. I also turned off the gas, so it would not light back up.

Today I installed the fuse, and it turned on again, tried to light 3 times, and then eventually the fan turned off after about 10 minutes.

Reading has led me to believe it has to be an issue with the thermostat, the circuit board, or the lo/high temp device that tells the unit to start or stop.

Since it starts, fires, and produces heat, I do not think it is the circuit board, so that leaves one of the other two options.

Are there any troubleshooting tips out there, or any ideas I have not thought about?

I hate to start throwing parts before I really know what is wrong.

Thanks for any advice,

Jerry
 
My furnace appears to have a timer
it seamed to run in a COOL DOWN mode for a few minutes ,
fan only... NO heat was being produced.... Put your hand over a furnace output vent see if it is getting cooler?


only notice it when I switch the thermostat OFF and it kept running
it did this each time so I figured it was meant to be.
 
My furnace appears to have a timer
it seamed to run in a COOL DOWN mode for a few minutes ,
fan only... NO heat was being produced.... Put your hand over a furnace output vent see if it is getting cooler?


only notice it when I switch the thermostat OFF and it kept running
it did this each time so I figured it was meant to be.
Mine does the same with normal operation. Once the thermostat calls for it to turn off, the fan continues for about 2 minutes to allow it to cool down.

My furnace will not turn off, even when it was 20 degrees above the set point. A totally different situation. For some reason, the furnace itself, is not receiving correct info from the thermostat, or it is not receiving the correct info from the lo/high device that tells the furnace to turn off or on.

Thanks for the comments,

Jerry
 
Sounds like thermostat to me, when you flip switch to off, should open line to furnace, and shut off in a min or so. You indicated you turned off heat on thermostat and nothing… Bingo.
 
What is the make/model of your thermostat?
Forest River uses many.
Some require reinitialization.
 
Pictures of thermostat attached. It used the RVComfort.ZC fpr two zones.

I'm not sure of the procedure for rebooting. I did have it removed from power for 24 hours before restoring power again today.

Thanks to all for the help.

Jerry
 

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Do a search on the forum for that thermostat, i see several posts on that stat with links to manuals.
 
I found my owners manual, and have searched here and found the same info. So far all I can find are instructions on how to "reset" the thermostat. I'm not sure I want to do that yet, because it appears of I do, I will have to reprogram it with all the original settings for 2 AC units and a furnace.

I'm not sure I'm up to fighting with that right now!!

I did go out and turn the heat back on today, and set the gas heat setting to 56 degrees. It was about that temp already, so I have been watching to see if it tries to kick on or not.

The good news is it was trying to fire up before regardless of what the settings were.

Maybe being disconnected from the power for 24 hours helped it "reset" and maybe it will work now.

In a couple of days I will put some new propane tanks on it and see what happens.

Thanks for the help so far, still open to any ideas or suggestions.

Jerry
 
Just to give everybody an update....

I put everything back together earlier in the week and turned the furnace on Friday morning. Set the thermostat to 60 degrees, and let it do its thing.

For two days now the furnace has run as expected, turning on and shutting off as expected. The thermostat always reads 60 or 61 degrees when I go out and check it.

It has barely broken 33 degrees outside here today, and the trailer is sitting right at the temp on the thermostat.

No parts were replaced and all I did was to power off the thermostat for about 24 hours and set it back up again. So for now, we are working as expected.

We shall see how this week goes....

Thanks for the help and suggestions,

Jerry
 
Back to the drawing board, I guess.

My furnace ran just fine for about 4-5 days, turning off and on as expected.

This morning I went out and it was 68 degrees in the trailer, thermostat set on 56 degrees. The furnace was running as hard as it would go.

I turned the thermostat to "off" and it still kept running. I killed the power to the thermostat, and it still kept running.

The only way to stop it was to kill the power to the furnace itself. I kept it off for several hours, and as soon as the power was restored, it immediately started pumping out heat.

I've ordered a new thermostat, and I hope that solves the problem.

Does anybody know an easy, clear, concise set of instructions for programming a new thermostat? I have 2 A/C zones and one furnace zone that need to programmed in.

Thanks,

Jerry
 
Here is the link to that thermostat. I suggest you download and follow the instructions. It just could be something has changed, electronic gadgets do that, without anyone knowing why.


Bob
 

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