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shane772 · 12-31-2015, 09:26 AM

I've searched and tried all I could with no success. My furnace failed to come on this morning so I went through a series of checks. Turned therm switch off, adjusted temp all the way up, switch back on. Fan came on furnace never lit, fan shut off after 4 mins. I know this is what happens with it fails to ignite so, I go check propane. 100# tank feels light so I switch over to the full 30# and try again. No change. I light the oven and let it run for a minute, go through process again, no change. I did the same thing with all gas appliances (except fridge) and they all light and worked properly. When none of that worked I attempted to loosen the propane line @ the furnace, it was too tight and too small for me to actually break the line so I don't know if gas is actually getting to furnace. I've probably cycled it 8-10 times now with no luck. Anyone have another step for me to try to diagnose this?
Edit: I believe it's a Suburban furnace can't see any info label but it has 2 round vents on the outside of camper.

monkey · 12-31-2015, 09:41 AM

I'm no expert by any means, but I'd check your "sail" switch... You didn't mention the brand of furnace, but just search that... They are known to go bad. Its a switch activated by the blower so it makes sure the blower is working before it turns on the gas for heat... I'm sure someone with more knowledge will chime in soon.... Monkey

shane772 · 12-31-2015, 09:50 AM

thanks monkey, I'll check google and see what I find.

mel s · 12-31-2015, 09:54 AM

Quote:

Originally Posted by shane772

I've searched and tried all I could with no success. My furnace failed to come on this morning so I went through a series of checks.

shane772
What is the make/model # of your furnace?
Mel
'96 Safari

shane772 · 12-31-2015, 10:24 AM

Quote:

Originally Posted by mel s

shane772
What is the make/model # of your furnace?
Mel
'96 Safari

I can't read the label in it's current place. The manual states it's a Suburban, and one of five models: SF-20FQ, SF-25FQ, SF-30FQ, SF-35FQ, SF-42FQ.

shane772 · 12-31-2015, 10:25 AM

It appears that the furnace will need to be removed to even check the Sail switch, or anything else for that matter. This is a real bummer.

Timay · 12-31-2015, 11:07 AM

2015 trailer - is there warranty?

Tim

firedoc · 12-31-2015, 11:07 AM

So the furnace starts blowing. Stand by the furnace and listen. If the sail switch is working it will respond to the air flow, send a signal that will start the gas and igniter. You should hear the clicking sound of the igniter trying to light. If you do not hear that sound and the furnace stops blowing, it is more than likely a defective sail switch. They are easy to replace but sometimes a pia to get to. Been there, done that!

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firedoc · 12-31-2015, 11:14 AM

Quote:

Originally Posted by firedoc

So the furnace starts blowing. Stand by the furnace and listen. If the sail switch is working it will respond to the air flow, send a signal that will start the gas and igniter. You should hear the clicking sound of the igniter trying to light. If you do not hear that sound and the furnace stops blowing, it is more than likely a defective sail switch. They are easy to replace but sometimes a pia to get to. Been there, done that!

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This is a picture of the switch for our furnace. I carry an extra.

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shane772 · 12-31-2015, 11:25 AM

Quote:

Originally Posted by firedoc

So the furnace starts blowing. Stand by the furnace and listen. If the sail switch is working it will respond to the air flow, send a signal that will start the gas and igniter. You should hear the clicking sound of the igniter trying to light.

Sail switch must be working. I did this and I can hear what you described. It sounded like it made 3 attempts at lighting before shutting itself down.

I've also tried removing the fuse for 5 minutes and trying again, no success.

shane772 · 12-31-2015, 11:27 AM

1 year warranty ran out in October. Although, paperwork shows Suburban carries 2 year warranty. Regardless, we are living in the 5th wheel at the moment and I can't "just take it in" so to speak. Haven't found anyone "mobile" yet that will come look at it.

mel s · 12-31-2015, 11:27 AM

Quote:

Originally Posted by shane772

I can't read the label in it's current place. The manual states it's a Suburban, and one of five models: SF-20FQ, SF-25FQ, SF-30FQ, SF-35FQ, SF-42FQ.

shane772
In that case I suggest you do whatever you have to do to read the model number of your Suberban furnace and then Google "sf-??fq Suberban furnace trouble shooting".
(I found enough information successfully repair my Suberban SF-42F furnace by Googling "sf-42f furnace troubleshooting").
Mel
'96 Safari

brewurown · 12-31-2015, 11:46 AM

I have Suburban furnace and it was working ok during the day and quit during the night. I turned out to be a bad controller board. The boards cost around 90 dollars. I was able to get to the furnace thru my kitchen cabinets. Replacing the board is not hard but I had to remove the furnace which was not very easy.

Qwert66 · 12-31-2015, 12:18 PM

The sail switch is accessible from the outside of your rig behind the cover.
The sail switch is working if you can hear clicking to try to start the flame.

What is also required is the following;
1-gas flow through the solenoid and small orifice. (you can "feel" the gas solenoid click) Sometimes the nozzle can get plugged but its rare on a newer unit.
2-proper air mixture (harder to check but wasps like to nest in the exhaust port and burner tube)

Food for thought