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Old 03-22-2021, 03:35 PM   #1
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THOR #20474
Furnace wouldn't run... Now it does

On our last camping trip, I was unable to run the propane furnace for a couple of days. When I turned the thermostat on, I could hear the blower start, and then I could hear the flame ignite several seconds later. After the flame was on for about five seconds, it went off. The fan stayed on and the flame on/off happened two more times, and then the blower went off. This happened two days in a row.

Then, I drove the RV to a new campground, and on a whim tried the furnace again. This time, it worked!

But now I'm wondering what the problem was and if it will happen again. And whether there are cheap parts I should have on hand.

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Old 03-22-2021, 03:59 PM   #2
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Originally Posted by AreVeeThereYet View Post
On our last camping trip, I was unable to run the propane furnace for a couple of days. When I turned the thermostat on, I could hear the blower start, and then I could hear the flame ignite several seconds later. After the flame was on for about five seconds, it went off. The fan stayed on and the flame on/off happened two more times, and then the blower went off. This happened two days in a row.

Then, I drove the RV to a new campground, and on a whim tried the furnace again. This time, it worked!

But now I'm wondering what the problem was and if it will happen again. And whether there are cheap parts I should have on hand.
It could have been something simple like air in the propane line that was purged out after the third run. Also are you able to check/monitor the house battery voltage? Maybe the voltage was at a higher and proper level at the next site.

A voltmeter is the first 'cheap' part you should have.
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Old 03-22-2021, 04:16 PM   #3
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If you can check the heater circuit board and find it shows any evidence of water/moisture thatís your problem! Either seal your outside compartment or buy a Dinosaur board on the Internet (Amazon).
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Old 03-22-2021, 04:49 PM   #4
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It could have been something simple like air in the propane line that was purged out after the third run. Also are you able to check/monitor the house battery voltage? Maybe the voltage was at a higher and proper level at the next site.

A voltmeter is the first 'cheap' part you should have.
Thanks for the ideas, but I don't believe it was air in the propane line, as I used the furnace fine before and after it temporarily didn't work. And I know that the coach batteries were fully charged.
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Old 03-22-2021, 04:50 PM   #5
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If you can check the heater circuit board and find it shows any evidence of water/moisture thatís your problem! Either seal your outside compartment or buy a Dinosaur board on the Internet (Amazon).
I'll look. Do I get to it on the outside where the exhaust is, or inside (under my fridge, I believe)?
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Old 03-22-2021, 05:26 PM   #6
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Use the SEARCH function as there are many threads on this subject.

For me, a brand new unit for first time use, my Attwood would spark and flame-out immediately. Then time-out after three tries.

I ended up taking the entire unit apart, a quite simple process after i got over the hurdle of doing so.

For me, the board was fine, but the spark tongs were not adequately creating the ignition.
I ended up bending/widening the tongs to make a longer spark + moving the tongs closer to the burner (where the propane is released).

That was 3 years ago. It's worked every time since (knock on wood!)

Others will say blow compressed air in the orifice.

You'll first need to remove the sidewall cover plate.
Keep us posted on your results.
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Old 03-22-2021, 05:30 PM   #7
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Could be a sticky sail switch, it didn't work and then it worked after you moved it. Or something else intermittent. These problems are tough to find sometime.
I call it the RRR..... Rough Road Reset.
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Old 03-22-2021, 08:13 PM   #8
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On the outside...remove the heater panel and it should be right in front of you. This is one of the most common causes for intermittent heater operation.
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Old 03-23-2021, 11:59 PM   #9
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I took the outside cover off, and didn't see any obvious concerns with the circuit board or anything else there. I'm going to have to become familiar with the furnace and troubleshooting it.
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Old 03-24-2021, 12:37 AM   #10
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The top of the circuit board will look normal. It’s the underside that will show signs of moisture, it doesn’t take much to cause it to malfunction.
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Old 03-24-2021, 12:41 AM   #11
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This is what mine look like!
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Old 03-24-2021, 01:13 AM   #12
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Your symptoms are classic wet circuit board symptoms that go away after the circuit board dries out. This has been a common problem with Atwood furnaces
before they relocated the control board si it doesn't get wet.

It is not the sail switch since it does try to light: a faulty sail switch would prevent that.
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Old 03-27-2021, 06:31 PM   #13
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Altitude

I had the same problem with my Four Winds Sprinter and found the issue was altitude. It would work at home or the dealer at 4000-5000 feet, but then not work when I was camping at 7-8000 feet. How different was the altitude of the campgrounds you used?
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Old 03-27-2021, 06:33 PM   #14
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Originally Posted by AreVeeThereYet View Post
On our last camping trip, I was unable to run the propane furnace for a couple of days. When I turned the thermostat on, I could hear the blower start, and then I could hear the flame ignite several seconds later. After the flame was on for about five seconds, it went off. The fan stayed on and the flame on/off happened two more times, and then the blower went off. This happened two days in a row.

Then, I drove the RV to a new campground, and on a whim tried the furnace again. This time, it worked!

But now I'm wondering what the problem was and if it will happen again. And whether there are cheap parts I should have on hand.
Could have been air in the line. Did you fill your propane tank prior to starting the heat? I've been advised to light the burners on my stove top to get all the air out that could have gotten in when filling the tank. The stove top is the highest point and this is a good idea. Bob Trice
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Old 03-27-2021, 06:39 PM   #15
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I had the same problem with my Four Winds Sprinter and found the issue was altitude. It would work at home or the dealer at 4000-5000 feet, but then not work when I was camping at 7-8000 feet. How different was the altitude of the campgrounds you used?
About 10 feet ASL at first campground and 700 feet ASL when it worked. I don't think elevation was an issue.
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Old 03-27-2021, 06:40 PM   #16
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Could have been air in the line. Did you fill your propane tank prior to starting the heat? I've been advised to light the burners on my stove top to get all the air out that could have gotten in when filling the tank. The stove top is the highest point and this is a good idea. Bob Trice
We had been using the stove before trying the furnace. And I could hear the rumble of the flame in the furnace for several seconds, so I'm pretty sure it lit, but it wouldn't stay lit. Now it does.
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Old 03-27-2021, 06:43 PM   #17
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Originally Posted by 16ACE27 View Post
Your symptoms are classic wet circuit board symptoms that go away after the circuit board dries out. This has been a common problem with Atwood furnaces
before they relocated the control board si it doesn't get wet.

It is not the sail switch since it does try to light: a faulty sail switch would prevent that.
We did have rainy weather, but I didn't check the furnace compartment for moisture.
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Old 03-27-2021, 08:18 PM   #18
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Originally Posted by AreVeeThereYet View Post
On our last camping trip, I was unable to run the propane furnace for a couple of days. When I turned the thermostat on, I could hear the blower start, and then I could hear the flame ignite several seconds later. After the flame was on for about five seconds, it went off. The fan stayed on and the flame on/off happened two more times, and then the blower went off. This happened two days in a row.

Then, I drove the RV to a new campground, and on a whim tried the furnace again. This time, it worked!

But now I'm wondering what the problem was and if it will happen again. And whether there are cheap parts I should have on hand.
I have a NEW24.1 and the furnace did not work . It had a bad sail switch. Come on Man! 😁
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Old 03-27-2021, 09:39 PM   #19
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If itís working Iíd quit worrying with it. Chalk it up to the RV gods.
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Old 03-27-2021, 09:47 PM   #20
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If itís working Iíd quit worrying with it. Chalk it up to the RV gods.
That's what I'm thinking. I liked pneumatic's post above mentioning "RRR..... Rough Road Reset".
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