Furnace Runs But Cuts Out After 10 Minutes

[Mike134]

Originally Posted by Larry-NC

No, no. Won't work.

The switch cuts off the furnace when the plenum gets too hot. By the time you have the grille off and connectors off, it's cooled down so much that it will be conducting again. You need to do a fast voltage reading across it. That's why one of my posts suggested wiring an LED across the limit switch for full-time information.

Presuming it's the high limit switch and you determine it's opening, still have the problem why? Typically not enough air flow. never worked on an RV furnace they have a belt drive for the fan or direct drive? Squirrel cage have a mouse nest? or some of the duct work?

[MR.M]

well yes yes does work . no reason for anything extra . having issues simple to test before it would cool off and close , After all you're trouble shooting the furnace should have access to it all ready to go to test continuity . the test that needs done is delta-t at that point if the furnace is getting to hot the switch is doing what it's supposed to . Too hot means problem with not enough air flow . that's the issue with hi limits without knowing the actual temp. no need to replace a switch that tests good cause it could be something else . normally when these high limits go bad they go bad open . if you don't test the temp you won't know if the switch is just getting weak and needs replaced or the furnace if over heating form some other reason . If the temps are with in specs and the hi-limit keeps going off replace ..

[Larry-NC]

Originally Posted by Mike134

Presuming it's the high limit switch and you determine it's opening, still have the problem why? Typically not enough air flow. never worked on an RV furnace they have a belt drive for the fan or direct drive? Squirrel cage have a mouse nest? or some of the duct work?

The Suburban SF-series furnaces are almost universally used in travel trailers and motorhomes.

They use a single 12 volt universal brush-type double-ended motor. Each end drives an impeller (squirrel-cage) blower via direct drive--no belt. One of the blowers brings outside air into the firebox--the exhaust flows back outdoors. The other circulates inside air around the firebox (inside the plenum) and through the trailer.

A mouse could build a nest in the impeller; it's unlikely, but they have been found in ductwork. Much of the ductwork is four-inch plastic hose (like clothes-dryer hose). Apparently it comes in 10' lengths. The installers are notorious for not taking the time to cut it to required lengths, but instead just cramming the entire hose segment in, in serpentine fashion. They have also been known to crush it to fit between structural framework.

RV owners have been known to place rugs over floor vents, or to replace the factory vents with ones that have dampers. The Suburban installation manual strictly forbids this. It also specifies the number of square inches of duct work and vents for each model and the number of square inches of return air space on the return air grille.

You can find the Suburban Installation manual in the "Library" on this site or by an easy internet search if you want more detail.

[Arvie1]

Originally Posted by Ned

The propane furnace on my 2014 Georgetown 351DS turns on and runs for about 10 minutes before turning off. It blows hot but doesn't reach the set temperature before it quits. If I recycle the "On" switch, it fires back up and does the same thing. It doesn't kick back on if I just raise the set temperature. The stove burners work and there is between 1/4 - 1/2 of propane in the single tank. Thanks in advance.

I had a similar problem in our 2011 Georgetown337ds. It seems that some genius put a heating vent directly under the thermostat. I closed the damper on that vent and have had no problems since. Hope your issue is as easy to solve.

[Artspe]

I have never worked on an rv furnace, haven’t even looked at mine but, I’m guessing that it probably has a flame sensor (like a thick wire that is in the flame when running). If it does have a flame sensor (could also be a spark igniter), it will act like this if going bad. Easy test is to GENTLY wipe the wire sensor with fine sandpaper and reinstall and see if it runs properly. If still not running properly, this is not the problem. If it does run properly, you will need to order a replacement flame sensor because it will only keep working for a few days.
DO NOT TRY THIS IF YOU ARE NOT COMFORTABLE WORKING ON YOUR FURNACE!!!

[Hoverdave]

Originally Posted by Ned

The propane furnace on my 2014 Georgetown 351DS turns on and runs for about 10 minutes before turning off.

Had this happen on my 340TS. Discovered mud wasps had gotten into the burner section. Once disassembled and cleaned the problem ceased and has not returned.

[Ned]

We found and removed debris but this did not fix the problem. The repair guy will be here tomorrow to replace the board in the furnace.

[cbcg710]

In regards to your furnace not reaching the set temp before it shuts off, make sure you don't have a vent pointed in the direction of the thermostat. Mine did that, and it was a vent at the bottom of the bedroom wall pointed directly at the thermostat.

[HeyJude]

Originally Posted by changing it up a bit

Good chance your control board is bad. Common problem I have changed several for people over the years. Just fyi, there are only three critical components to the furnace; the blower.the sail switch, the control board, and the thermostat.
Hope this helps.

We are having the same problems, do you have a parts diagram? Maybe an exploded view of the parts.

[rockfordroo]

Originally Posted by HeyJude

We are having the same problems, do you have a parts diagram? Maybe an exploded view of the parts.

Find your make/model number, then google it with "owners manual" after and you'll find the manual.

[Larry-NC]

Originally Posted by HeyJude

We are having the same problems, do you have a parts diagram? Maybe an exploded view of the parts.

The Suburban SF-series are very easy to find. There is a user manual, an installation manual, and a couple of good service/troubleshooting manuals.

Start by looking in the "Library" found in the green bar at the top of every forum page.

[rockfordroo]

Here's a Suburban SF manual:

[Ned]

Turns out it was the control board. The service guy originally ordered a universal replacement board but wouldn’t fit. He then ordered the dinosaur replacement which did the trick. Thanks everyone for the help.

[Bama Rambler]

Thanks for letting us know the resolution to this. It helps us give better advice as well as helps others with the same symptoms know what it may be in the future.