Furnace Issues

[BudPlotts]

We had a 2021 Solitute 377MBS and are having issues with furnace not continue to run. The rig has a suburban SF-35Q and when I turn it on it will go through all the steps and the furnace will ignite (I can feel the heat coming out of the exhaust) but will go out shortly after, this will repeat 3 times before shutting down. I did replace the limit switch and it it worked for us one cold morning but it has returned to normal state of not staying lit. Should I try to replace the limit switch again (seems like a cheaply made part) or replace the control board? Has anyone had this same issue before?

[Country Campers]

BudPlotts

Is there any other items , fridge ,stove,, water heater, running when this happens?

Brian

[howson]

We had a 2021 Solitute 377MBS ....

Noted that was your first post so just want to write and welcome you to the forum. There's a letter the moderators put together to help newcomers orient themselves with the forum. I hope you'll check it out when you get a chance.

https://gdrvowners.com/forum/main-fo...to-new-members

Again, welcome!
Howard

P.S. There's plenty of folks here that will help you sort out the propane/heater issue. I'll be reading along!

[BudPlotts]

The stove and oven work properly, all the other items are running but are on electric.

[ncitro]

The stove and oven work properly, all the other items are running but are on electric.

I would change the board but thats me. I tend to assume its the board first lol. If the switch is cheap I would order one too, if they are available on Amazon its easy to return whatever you do not need, or keep it for a future repair. I am a big san of the Dinosaur boards, thats what I have used in my water heater and a buddies furnace. They are great at troubleshooting too, if you give them a call they will have you do some basic testing and help you figure out what you need. If you need the Fan 50 plus (I think thats the Suburban board) its available on Amazon Prime.

https://www.amazon.com/Dinosaur-Elec...b-8a79de2d236f

[colan]

I second the board. On a Suburban furnace which are pretty solid boards are the most common failure.

In addition to experience what is pointing to the board is the fact that the furnace is lighting for a few seconds. The control board sparks for 7 or 8 seconds. If the board doesn’t think there is a flame after eight seconds it closes the gas valve, stops sparking, enters a purge cycle and try’s to ignite again. There is a maximum of three ignition attempts.

So... if the board isn’t seeing a flame, why isn’t it the flame sensor? The flame sensor is the igniter itself, through what is called flame rectification there is a small current flow across the igniter electrodes which the board detects. Given the fact that the igniter works, this points away from the igniter/flame sensor. The second reason I doubt it is the igniter is i seldom replace these, one in the last four years.

For a replacement board would suggest a Dinosaur Electronics Fans 50 Plus Pins. Made in the USA and has a three year warranty.