Podmods, Maintenance, Tips and Tricks: furnace ignites intermittently

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furnace ignites intermittently

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URL: http://www.rpod-owners.com/forum_posts.asp?TID=14104
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Topic: furnace ignites intermittently

Posted By: mikeyg2347
Subject: furnace ignites intermittently
Date Posted: 11 Oct 2020 at 7:12pm

While camping this past week my furnace wouldn't light regularly. I tried lighting the stove burners first to get gas flowing and pulled the igniter to make sure the ends of the wires hadn't vibrated too far apart. Not sure what the distance between them is supposed to be but I pinched them a little closer together, about 3/16". The fan comes on and sometimes the igniter clicks and sometimes it doesn't. When it clicks I'm in business. I have a brand new thermostat that has been working fine to this point and the connections are tight. The gas tank is full of fresh gas. Naturally, now that I'm home it comes on every time I try it, but now that we're into fall I'm concerned about it failing completely. Any clues?

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Mike

Replies:

Posted By: Tars Tarkas
Date Posted: 11 Oct 2020 at 7:17pm

I don't know much about this, but elevation can play a part in this. Were you camping above 8,000 feet?

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2010 176
FJ Cruiser

Posted By: mikeyg2347
Date Posted: 11 Oct 2020 at 7:59pm

Nope. Between 5-6,000' at the most. I've camped higher than that with no problems.

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Mike

Posted By: StephenH
Date Posted: 11 Oct 2020 at 8:28pm

Are the rest of your gas appliances working okay? Turn on the stove. Then try to get the furnace going. If the flame on the stove drops dramatically, then there is a problem with either the regulator or the acme nut connecting to the tank. I had one of the acme nuts go bad during freezing weather. I replaced the regulator and it didn't fix it. I did not know that the anti-backflow valve in the acme connector can go bad. The symptom was what I described.

Other options are that there is something in there (wasp nest?) that may be blocking things. Do you have bug screens over the vents? If not, then check to make sure nothing is in there that does not belong. Even if you do have screens, it would not hurt to check.

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StephenH
Happy is the man that findeth wisdom,...

http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods
Former RPod 179
Current Cherokee Grey Wolf 24 JS

Posted By: mikeyg2347
Date Posted: 11 Oct 2020 at 9:18pm

Everything is working fine except the furnace. We do have a serious wasp problem so I'll open it up and see what's in there. What puzzles me is, if I hear the igniter click, then it fires right up.

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Mike

Posted By: StephenH
Date Posted: 11 Oct 2020 at 10:05pm

However, if something like a mud dauber nest is blocking the thermocouple, the furnace might not be registering that it is lit and shuts down.

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StephenH
Happy is the man that findeth wisdom,...

http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods
Former RPod 179
Current Cherokee Grey Wolf 24 JS

Posted By: offgrid
Date Posted: 12 Oct 2020 at 6:57am

It might be the igniter or the sail switch activating intermittently. The fan comes on first when the tstat calls for heat, the sail switch senses the airflow and closes, then the control board waits about 15 seconds to be certain the furnace is purged of any propane before activating the DSI to light it.

You pretty much need to take the furnace out to get in there and inspect things, its not hard really. Here is the manual, there is a troubleshooting section toward the end.

http://bryantrv.com/docs2/docs/subntnew.pdf - http://bryantrv.com/docs2/docs/subntnew.pdf

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1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

Posted By: mikeyg2347
Date Posted: 12 Oct 2020 at 1:57pm

Thanks, guys. The manual was especially helpful. I pulled it out and cleaned it as thoroughly as I could without tearing it apart. It wasn't as dirty as I thought it would be considering how much dust finds its way inside the Pod. Some dead bugs and dirt inside the burner area, no wasp nests anywhere. The electrode wires were a little farther away from the burner than the specs call for plus they were a little too far apart. I adjusted that and put everything back together. Getting the outside ducts to line up and slide onto the unit was the fun part. On your knees you have to torque yourself around the corner of the kitchen counter and while using your hands to line up the ducts with the furnace outlets you simultaneously push with one knee. I was grateful for yoga at that point. Once everything was put back in place it fired right up on three consecutive tries. Got my fingers crossed that it stays that way. Thanks again for your help.

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Mike

Posted By: offgrid
Date Posted: 12 Oct 2020 at 2:48pm

Congratulations! Glad it worked out for you.

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1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

Posted By: Colorado
Date Posted: 13 Oct 2020 at 9:44am

To issues with furnaces:

1. The furnace on my 2015 Model 178 runs the fan and fails to start when the battery voltage is low. When I switch to my 2nd battery, the furnace fires right up.

2. My thermostat would not work the other day (Dometic Heat/AC/Fan) and the furnace would not come on on one of those cold Colorado mornings. I tracked the problem down to a bad circuit board in the roof top AC. Apparently the furnace thermostat wires run to the AC unit, then to the Thermostat. I discovered that the red and white wires going to the thermostat only had 2.2 volts (not 12 Volts). Once you take off the cover of the AC, there is an electrical panel on the passenger side. The circuit board is under the cover and is held in place by 4 plastic clips. The board cost $48 and has about six wires/plugs which need to be unplugged/replugged into the new board.

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Colorado

Posted By: mikeyg2347
Date Posted: 13 Oct 2020 at 11:38am

Interesting point about the voltage. Seems like I was about 12.4 volts when the igniter wasn't kicking in. I'll have to monitor that if I have any more issues. I pulled my air conditioner and replaced it with a vent this summer, so no problem there. Thanks for the input.

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Mike