Another Furnace Question

[rubyslippers6232]

We used our furnace a couple weeks ago on a camping trip. It worked well when we first turned it on each morning. But once it reached the desired temperature and shut off, and then tried to start again, it didn't work. We could hear the clicking, and the fan was blowing, but it never ignited after the first cycle. Any ideas?

[Alaskan]

Well if you're hearing the clicking and the fan's working it probably not a low voltage problem.

Sounds like a propane flow problem....there is a gas valve on the unit that is activated by an electric solenoid, which is controlled by the circuit board

One of those might not be doing their job I'd guess when the system has become warm.

[skater]

I'm with Alaskan. In particular the two furnaces in my parents' camper had a very similar problem - they'd light the first time but then afterwards they wouldn't. Unfortunately we learned of this problem over a very cold Thanksgiving trip.

In that case it turned out to be the board, if I remember correctly.

[Alaskan]

ya....that kinda makes sense, the circuit board warms up and something inside it expands just enough to not activate the gas value on the next lighting cycle.

If you're going to just simply replace the board, which is very easy, don't buy the Atwood replacement as its missing the surge protection

The best replacement board is from Dinosaur Electronics...same for the water heater

http://www.dinosaurelectronics.com/

If you need assistance in choosing the correct board for your application use their "Customer Service" form.....

This is what the furnace board looks like...takes all of about 5 minutes to install .

Boards can be purchased online at several places shown at Dinosaur's website such as Mark's RV.com

This same UIBS board is used on the water heater with the optional clear plastic cover..

Installation pictures tomorrow...

[rubyslippers6232]

Thanks Alaskan and Skater, we'll look into this. Very helpful!

[Alaskan]

Control Board replacement....

Remove the tin cover at the base of the furnace as seen in this picture below, the Control Board is attached to the back of that cover....2 screws, one down there in the lower right corner and one up there in the center...both can be seen in this picture.



This is what the board looks like....4 screws and 2 wire plugs. Simply replacement

[Alaskan]

rubyslippers6232....

In the first picture above, in the lower left you'll see the gas valve. You might want to check and make sure the wires are firmly plugged onto it..

[skater]

I asked my dad about this and he thought it was the board, too, but suggested that you all the connectors off the board and clean them and see if that helps first.

We talked about it being one of the safety switches, but we decided that it wouldn't be trying to ignite if it was one of those (for example, if the sail switch for the fan wasn't working, it wouldn't even try to ignite).

Still, the part that bothers me about the board explanation is that if you're hearing the clicking, it sounds like the board is actually trying to light the propane. So I would wonder if the gas valve is going bad instead - or perhaps the failure mode of the board is that it's not telling the gas valve to open up when it should.

Also, and this is probably a silly question, but you are opening the propane tank valve all the way, right?

[Alaskan]

Good idea your dad had to unplug the connectors and reconnect them, especially that white connector with several wires as the red wire on it goes to the Gas Valve

Skimming the Owner Manual for that furnace it does point out that there is a circuit breaker and I do see it in there on the right, has the number 5 on top.

Also mentions there is a relationship of the thermostat to the gas valve..

Thermostat about $20
Control Board...mail order about $90

New Furnace @ eBay today: "Buy it Now" $285
http://cgi.ebay.com/ebaymotors/ATWOOD-1 ... enameZWDVW

[rubyslippers6232]

Wow, this is so helpful. I will check all the connections before doing anything else. Skater, I did have the propane tank open all the way, but that was a good question.