Furnace stopping working last night

[eagle55]

This morning was a chilly one here! Was boondocking in what are the very last good autumn RV usage days before winter sets in here in Southeast Alaska. This morning I discovered that while the blower fan would run for a specific time before shutting down, there was no burner firing up with the usual click of the solenoid. I couldn't hear the igniter either.

So am wondering what to check first. The igniter, the control board, or something else? The dealer is in Whitehouse Canada and I cannot take it up there because of border restrictions so if I'm going to use this new Jayco, I'm going to have to figure if out myself, with help from you of course!

The trailer is a 2019 20' Jayfeather and the furnace is a Dometic with a basic bimetal strip thermostat. Have plenty of propane, and the batttery was up at 12.6v. Thank you for any light you can shed.

[Marcm157]

Has it been working and just experienced the problem last night? If you have fan but no ignition I would check the sail switch or the flame sensor first.

[Randy]

X2 on the sail switch

[Grumpy]

If boon docking the battery may be getting a little low and the blower is not running at full speed so the sail switch will not close. Can you connect your tow vehicle and see if anything changes?

[Route 66 Traveler]

Got propane???

[Neo1130]

Out of propane, sail or flame switch.

[eagle55]

Thanks for your suggestions everyone.
The problem with the furnace came on all of a sudden our last night out sometime, for the first time, and there isn't any intermittent aspect to it. It worked perfectly and reliably, and then it didn't.

As for the voltage, we had a sunny day the day before, and the solar charger showed a good boost charge of 14.4v for a couple hours before going to float for the remainder of the day at 13.7v until sundown. The batteries (2)12v nearly new were in good charge condition when the problem started. Yesterday afternoon we broke camp and came home, plugged into shore power, but the problem persists.

Propane pressure seems fine, the flame on the stove top burners are strong and blue, the fridge and water heater working fine as well.

I'm a retired electrician by trade, but have never worked on a rv furnace before. Is there a resource that can provide me an online service manual or perhaps schematic or wiring diagrams? I like to have as much info on hand as possible before I get started..
Thanks again!

[Route 66 Traveler]

See if there is a reset switch on the top cover. Sometimes hard to see, might need a flashlight.

[Route 66 Traveler]

See if this will help. Fault codes on page 8.


https://manuals.heartlandowners.org/...wood%20AFM.PDF

[RichR]

2X Check the fault codes.

[eagle55]

I have the furnace out and 12v power on it. No gas hooked up, and when I cycle it by bumping the T-stat wires together the blower comes on, the sail switch does close when checked with my multi meter for continuity. The control board has one flash almost immediately after the fan spins and that's it. Is that the limit switch code, or just the normal startup? Not sure what the 3 second pause they refer to in the manual is. Is that meant to be a 3 second pause where then the flash repeats itself? May need to check the limit switch next.

STANDARD 3 TRIES FOR IGNITION CONTROLS
DIAGNOSTIC CHART
FAULT
LED INDICATION
LOCKOUT

Internal Circuit Board Failure
Steady On, No Flashing
Hard

Limit Switch/Airflow Problems
1-Flash With 3-Second Pause
Soft

Flame Sense Fault
2-Flashes With 3-Second Pause
Hard

Ignition Lockout Fault
3-Flashes With 3-Second Pause
Soft (1hr.

[eagle55]

So was able to get the furnace to run again! Thanks for your input on this.. Still not sure what was wrong however, so may be having to revisit this again later. I basically removed the sail switch, blew out a bit of lint on the outside, and through the openings with canned air. Also moved all the plugs back and forth in case of a bad connection.. When I got done looking for the problem I turned the unit on, and heard the igniter and the gas solenoid. The codes were confusing in that the LED flashed once each time I energized the circuit, and again on de-energize. This is probably a normal event that happens each time the furnace comes on..

Anyway, the heat is on, and we are heading back out for what may be the last chance for a boondock camp this year!
here's one of our preferred boondocking spots.. Front row seat to bears, stary nights and in fact the other night was a real treat, a big fireball meteor that floated by fairly slowly! Took our breath away that one!

[Screwby]

Originally Posted by eagle55

So was able to get the furnace to run again! Thanks for your input on this.. Still not sure what was wrong however, so may be having to revisit this again later. I basically removed the sail switch, blew out a bit of lint on the outside, and through the openings with canned air. Also moved all the plugs back and forth in case of a bad connection.. When I got done looking for the problem I turned the unit on, and heard the igniter and the gas solenoid. The codes were confusing in that the LED flashed once each time I energized the circuit, and again on de-energize. This is probably a normal event that happens each time the furnace comes on..

Anyway, the heat is on, and we are heading back out for what may be the last chance for a boondock camp this year!
here's one of our preferred boondocking spots.. Front row seat to bears, stary nights and in fact the other night was a real treat, a big fireball meteor that floated by fairly slowly! Took our breath away that one!

I’ll bet it was a sticky sail switch. I’ve had the issue on my big camper and my buddy’s camper. Sticky sail switch caused furnace to try to run, blower blew for a set time, then furnace turned off. The sail switch wasn’t working correctly so the furnace didn’t think there was adequate airflow thereby shutting itself down. Frustrating lol

[eagle55]

Originally Posted by Screwby

I’ll bet it was a sticky sail switch. I’ve had the issue on my big camper and my buddy’s camper. Sticky sail switch caused furnace to try to run, blower blew for a set time, then furnace turned off. The sail switch wasn’t working correctly so the furnace didn’t think there was adequate airflow thereby shutting itself down. Frustrating lol

Quite possible. On that thought I think I will order one to have on hand in case. It also could have been that ball of lint I saw on it, maybe preventing it from closing the contacts.. sigh..

[sturgissteele]

Great trouble shooting! Glad all is good and enjoy that spot! Looks fantastic!

[dvspl]

Nice work! That spot looks beautiful and we sure miss our days in Alaska. Enjoy your camping there!