Suburban furnace dead

[Brian S]

Without propane connected to the furnace, it should try 2 - 3 times to ignite and then lock out. The fan will continue to run. At least you will hear the spark ignition trying.
If the fan runs normal and the board does not try to ignite after a short pre-purge of the combustion chamber, then I would look at the sail switch. It should be easy to jump out two terminals on that for a test.

[Beauty & the Beast]

I had to finish a side job tonight and will go vote tomorrow but should be able to get back to testing this week and I will report back with my findings
appreciate all the responses 👍

[Country Campers]

I have found that trying to jump past the sail switch does not work. I have tried this on a spare furnace. I believe that the sail switch has some sort of resistance built in that the board needs to see a specific voltage before allowing ignition. You could make a set of jumper wires from your battery to the furnace to by pass all of the other wiring in the RV , remember to use an in line fuse for protection. I have a 12 volt power supply to do testing with but not every one has that. I would have to agree with the others here that the board is probably the culprit.

Brian

[colan]

Since it's not firing up, the high limit switch is likely not the issue.
And just to confirm... The blower motor is not turning on either right? If not, it rules out the sail switch.

If you have good battery voltage, then the control board is the most likely culprit.

Jim

A sail switch that is stuck in the closed position will cause the fan motor not to run.

The control board before sending power to the motor checks to see if the sail switch is closed. If the sail switch is closed the board goes into lockout and doesn’t send power to the motor.

[Brian S]

A sail switch that is stuck in the closed position will cause the fan motor not to run.

The control board before sending power to the motor checks to see if the sail switch is closed. If the sail switch is closed the board goes into lockout and doesn’t send power to the motor.

So in that case. disconnect one side of the sail switch (remove one wire) and see if the fan starts. Of course also check for power to the fan motor.

[Beauty & the Beast]

Shore power or just 12v same 9v
fridge, front cap and interior lights have 12v
lights in front storage have low voltage not working
Traced wire and it looks like it travels thru the storage lights then goes to a box that has a million wires going to it so somewhere there is a loss of voltage
I am not having any luck
Also blue with white stripe wire that connected to the off side of the little switch on furnace is not connected to anything very strange
Calling GD tomorrow might need a tech to solve this one 🤔

[howson]

Shore power or just 12v same 9v
fridge, front cap and interior lights have 12v
lights in front storage have low voltage not working
Traced wire and it looks like it travels thru the storage lights then goes to a box that has a million wires going to it so somewhere there is a loss of voltage
I am not having any luck
Also blue with white stripe wire that connected to the off side of the little switch on furnace is not connected to anything very strange
Calling GD tomorrow might need a tech to solve this one 🤔

Technically it's not "through" the storage lights, the furnace should be in wired in parallel with the storage lights if they are on the same circuit. (If it really is "through" that's the problem! All of the components on the same circuit should get 12v, thus wired in parallel.)

Is there a fuse in your Convenience Panel labeled "Furnace" (in circuit 5)? If "yes", when you pull the fuse out and measure the voltage (both sides) there should be 12v on one and nothing on the other. What do you get?

[howson]

Beauty & the Beast -- also, if you do pull that fuse what stops working in the camper (12v related)?

[Beauty & the Beast]

Beauty & the Beast -- also, if you do pull that fuse what stops working in the camper (12v related)?

I will try that tomorrow 🤔
I can pretty much see everything with that wall removed
I will turn everything on and see what happens when I remove fuse
All basement puck lights r not working

[howson]

All basement puck lights r not working

The drawing I have access to may be wrong--so keep that in mind--but if there's an issue on circuit 5 (and when you remove the fuse) the lights in the "garage" should be affected (turn off), as well as the two in the closet slide-out in the garage, and the two lights for the ramp. (Please don't ask why these are on the same circuit as the furnace--beats me!)

[Beauty & the Beast]

Thanks I will turn them on and see what happens

[Beauty & the Beast]

As suspected no help from grand design on a $120000 coach
back when I had my heartland i got better service
Sorry had to vent

[TucsonJim]

As suspected no help from grand design on a $120000 coach
back when I had my heartland i got better service
Sorry had to vent

In your first post, they suggested changing the control board. Have you done so yet?

According to your Momentum Owner's manual, Suburban furnaces are covered by a two year warrant from the time of purchase. If you're still in that two year period, I'd suggest you try contacting Suburban for warranty repairs. However, since you purchased the unit "used", it may not be covered by the warranty.

Here is a link for the Suburban RV warranty and how to contact them.

https://www.airxcel.com/docs/default...y.pdf?sfvrsn=4



Jim

[Beauty & the Beast]

Got 12v back it was a loose connection on one of the wago quick connect all basement lights working now
still got error and dead nothing happens
Also there are 2 blue wires one goes under the fan the other has a white stripe that went to the off side of the switch and has a wago on the other end connected to nothing there is no wire behind wall that it connects to
this thing was never hooked up
Missing a wire
thank you grand design
Not sure why this would not be connected
This should not be happening and is very disappointing probably why I'm getting error
Not a happy camper

[howson]

thank you grand design...Not a happy camper

I'm not understanding why you blame Grand Design. Your trailer was manufactured in 2019 and you bought it used. Is your contention the furnace never worked? I find that hard to believe, even though that is apparently exactly what you wrote in post #1. Do you accept any responsibility for buying a used trailer without (apparently) operating all of the RV's systems? Why didn't you get an inspection done by a certified RV inspector?

This forum exists to help with technical issues. There's a gang of folks that are more than happy to do just that and will continue to help you as we can, but please refrain from any further vents directed at Grand Design.

Thanks in advance for your understanding and cooperation.

-Moderator Howard