60 replies to this topic

[leadsled9]

I believe so. The fridge was maintaining, but I never checked the stove, so I can't say whether it had the same problem. What you described though, with the furnace running for a few seconds and then shutting down sounded exactly like my problem. I don't even think about it anymore, as I just loosen the fitting, reattach it and leave for my trip. Once I do that it is never a problem on the road.

I hope this helps.

Which fitting are you loosenig? Are you talking about the main connection to the propane tank?

[Phird05]

Which fitting are you loosenig? Are you talking about the main connection to the propane tank?

Yes, the main fitting at the propane tank. I leave the tank valve on when doing this to have a little bit of pressure at the fitting, but there is a check valve in the tank so you won't have any gas leak out of the tank when you loosen the main fitting. You will hear a slight hiss for a split second when you loosen it. I then simply attach the fitting and that has solved the problem. Again, I have only had this problem 2-3 times in the last year, so it is a very hit or miss problem, usually after I have not used the furnace for an extended period of time.

I hope this helps.

Paul

[MarkBC]

1) As I posted a couple weeks ago, I've had the igniter-clicks-but-furnace-won't-light problem, usually when the battery is low -- but recently sometimes when the battery is mostly full.

2) And also repeating a previous post, I have started having a wimpy-flame problem, usually when the propane tank is getting low -- but not always. So, about #2 first, I went ahead and took out the burner to see if it looked clogged. I said I'd post pictures of this step, but it was so easy/obvious (with my Suburban DD17DSI, anyway) that I didn't bother: Remove 2 screws to remove the grill. The rectangle that has the furnace sight glass is attached to the end of the burner -- remove the 6 screws around the rectangle's perimeter and (after disconnecting the wire to the igniter) pull that rectangle with attached burner out the front...that's all.
So, looking at the burner I see the same kind of corrosion that I saw on the refrigerator burner...but the holes still look plenty big, so I don't think the problem is there. But I'll give the holes a little wire-brush-scrubbing anyway. And/or maybe I just need to try Phird05's suggestion (above) next time I get wimpy-flame.

Back to #1: From the symptoms, I wonder if the problem is a balky sail switch, as somebody has suggested. That would fit the original symptom (seen when the camper was new) that when the battery is low the furnace won't light: The low power doesn't drive the fan fast enough to activate the sail switch. And now -- with the new symptom that it sometimes won't light even with a mostly-full battery -- it could still be the sail switch, but now the sail switch is just sticky or "corroded" or something like that, so even adequate fan-blowing won't make it sail at times.

My question: Can someone tell me where I'd find the sail switch on the Suburban furnace? I just bet I'll find it a little stiff and some cleaning and/or a little Tri-Flo will fix it. Thanks.

[DLN]

The sail switch will be just forward of the fan in any heater. That switch is really the weak link in the whole safety system in these heaters. They generally fail internally due to the fact that they swing back and forth as you drive and simply wear out so adding lube to it won't solve the problem.

[MarkBC]

The sail switch will be just forward of the fan in any heater. That switch is really the weak link in the whole safety system in these heaters. They generally fail internally due to the fact that they swing back and forth as you drive and simply wear out so adding lube to it won't solve the problem.

Thanks. So now I just need to find the fan...guess I need to remove the whole furnace, as I expected/feared.
The sail switch in my furnace hasn't actually failed (assuming that's the problem) -- the furnace still lights most of the time. And when it doesn't light the symptoms fit with a sail switch that's not "sailing" far enough to activate the switch.

I didn't go anywhere for T-Day (no camping), after all. My next major outing will be between Xmas and New Years. I plan to head for central and eastern NV -- maybe even far-western UT -- so I gotta be ready for cold. That's my driver for making sure my furnace is working properly (even though I have a Wave 6, too).
But it's snowing here in Bend, so I don't think I wanna work outside right now.

[natjwest]

To follow-up with the original post in this thread, I got my furnace working today. Muchos gracias to Rob in MT for his earlier post in this thread to check polarity. That was the culprit.

I had already given that a cursory check since the black wire was on the positive battery post and white to negative, but who knew that the cable coming off my battery, going to the fuse block was reverse-colored? All the other electrical systems were working fine (not that there's too many of them), the fan was spinning, lights and vent-fan worked, but when I reversed the wires, the furnace click-whooshed first try. Now I just need to properly swap the wires so the colors make sense.

[davidshourd]

I have a similar story, I went out camping this last weekend and I kept getting the "ignition lockout fault" (three blinks of the LED). fan spins, burner ignites for maybe 2-3 seconds then stops, three times then locks out. well after trying that maybe a dozen times and reseting with the reset switch it would fire and run fine through the night. next morning, same thing, kept giving me the lock out code. so I got home and pull the burner apart to check for build up, it was really clean and nothing obvious was observed. so I tried again and I got it going after abotu three resets. Any thoughts? I turned the pressure up slightly in the regulator (3/4 of a turn) after reading something somewhere else, did not seem to make a difference. battery is fully charged, fan is running, sail switch hits, burner ignites for 3 seconds then off. only thing left I can think of is the board is bad and somehow not "proofing" there is flame some of the time.

[Connecticut Yankee]

Thanks to everyone who posted on this problem. I just learned that my furnace won't light problem was low battery. Had enough juice to run fan, but not ignite. Soon as I charged the battery, problem solved. I have an '82 Grandby but don't know what kind of furnace was installed back then.

[Sam]

Sounds like we have two separate furnace issues on this thread. Mine has the, it fires runs for a few seconds then shuts off problem. I have suspected it to be a regulator, OPD valve issue. I have not tried Phird05's suggestion of loosening the LP line at the tank to bleed it, but I'm pretty sure it will work like he says. Question is, what does this mean? If bleeding the line works then what is the root problem?

[WillTheThri11]

Curious, how do you check polarity at the heater?  My battery seems to be hooked up correctly and is reading 12.9V.  I guess I could check polarity at the fuse panel?

 

My heater fan runs and blows air out of the bottom register.  I'm guessing this is correct since the sail switch seems to engage and the gas valve clicks, i hear the ignitor sparking but it doesn't light and then the valve clicks off.  Polarity seems like the easiest thing to check but i need to know where to check it i guess.

Edited by WillTheThri11, 20 September 2019 - 08:31 PM.