Atwood Furnace not lighting

[wavery]

I have an Atwood Furnace, model #7916-11 in my PU. I can't get the darn thing to light. I checked the fuse, it's OK. The switch on the furnace and on the thermostat are on and the thermostat is turned up.

When I first turned it on, the fan came on and I could hear the igniter click. It clicked 3 times in about 30 seconds, then shut off. I turned everything off and even removed the fuse from the fuse panel. I waited 5 minutes (as per instructions in the feeble manual). I turned everything back on and the same thing happened.

I have a full tank of propane and the stove, fridge and hot water heater are working fine.

Does anyone know where I can get a trouble shooting guide for this thing? I'd like to know what the voltage is supposed to be to each one of the contacts.

The other thing that I noticed is that the voltage drops severely when the fan comes on, when I am on battery power. The voltage at the batteries and at the fuse is 12.5 and doesn't budge when the heater comes on but the voltage at the heater drops from 12.3 to 11.6 when the fan is running. The inside lights also dim.

I have been suspect of the converter for a while but that doesn't explain why the furnace won't light because when I have the generator running, the voltage doesn't drop.

[tlhdoc]

Will it light if the generator is running or when plugged into shore power?  It is normal for the lights to dim when another 12 volt item is turned on.

[wavery]

Will it light if the generator is running or when plugged into shore power?  It is normal for the lights to dim when another 12 volt item is turned on.

It doesn't light when on shore power either. The lights don't dim and voltage doesn't drop while on shore power.

I suspect that there may be a bad relay in the converter but I'm convinced that is a separate issue from the furnace. I'm tempted to just wire the furnace directly to the battery (fused, of course). I may do that just as a test.

[tlhdoc]

The lights and things not dimming on shore power is normal.  Dimming is normal when on battery power.  Could there be air in the gas line?

[wavery]

The lights and things not dimming on shore power is normal.  Dimming is normal when on battery power.  Could there be air in the gas line?

Well, I've got gas as far as the stove. I suppose there could be an air pocket between the stove & furnace (about 2' of line). I'll go down tomorrow and crack the line at the furnace and let some gas out. I'll come back an hour or so later and try to light it then. I sure hope that's it.

Is there any way to check the igniter, other than just hearing the clicking sound?

[wavery]

The lights and things not dimming on shore power is normal.  Dimming is normal when on battery power.  Could there be air in the gas line?

I opened the gas line at the furnace and turned on the propane until I had a strong gas smell. Closed up the line, with the propane still turned on. Let is set for a couple of hours with a fan blowing the fumes away from the PU. I checked for gas leaks and found none. Turned on the furnace and got the same thing. I could hear the igniter click when the fan came on, then again about 20 seconds later. It clicked a total of 3 times then the fan shut down. The heater never ignited .

[tlhdoc]

OK so the simple stuff checks out OK.  Here are a few other things to check.
 
I would try giving the burner a good cleaning.  The burner orifice or the exhaust could be blocked.  The electrode could be out of adjustment or defective.

[wavery]

OK so the simple stuff checks out OK.  Here are a few other things to check.
 
I would try giving the burner a good cleaning.  The burner orifice or the exhaust could be blocked.  The electrode could be out of adjustment or defective.

That sounds about right. Do you have any idea where I could get a manual for one of these things? I emailed to Atwood and they said, "Take it to an authorized dealer".  That will be the day...... :p

I hate to start tearing into this thing when I have never even seen one before. It's probably simple enough but I don't want to make a big project out of a simple job.......if you know what I mean.

[pfaust]

HI: Try "www:/bryantrv.com"

They have a lot of manuals there and if they don't have yours you can E-mail them and ask for help.

[wavery]

HI: Try "www:/bryantrv.com"

They have a lot of manuals there and if they don't have yours you can E-mail them and ask for help.

Thanks a lot. I emailed them. I'll keep you posted on how it goes.

For anyone else that might like that link, this is their website:
http://www.bryantrv.com

[oldmoose]

I had that problem and they had to replace a circuit board in the furnace. Fortunately it was under warranty at the time. If you need a quality service man, I have one who makes visits to your home. Of course he charges to drive there from OC, but it's easier than driving there. I'm going to have him do a service on our rig shortly. Let me know.

Moose

[wavery]

I had that problem and they had to replace a circuit board in the furnace. Fortunately it was under warranty at the time. If you need a quality service man, I have one who makes visits to your home. Of course he charges to drive there from OC, but it's easier than driving there. I'm going to have him do a service on our rig shortly. Let me know.

Moose

Thanks Moose,

I got another email from Atwood this morning. They gave me a trouble shooting guide in PDF format. I'm going to go through all of the steps in this guide. If I can't get it going, he gave me a phone # to call him from in front of the furnace with a voltmeter in hand.

You just can't ask for better than that. Their first response was because they had no idea what abilities I had. I replied to that email telling them of my qualifications. That is when they replied very positively.

[tlhdoc]

I am glad that they are sending you the info.  Let us know how you make out.

[wavery]

I've narrowed my heater problem down to the gas valve. It has a couple of electric solenoids on it and they appear to be stuck.

I emailed my contact at Atwood (last Tuesday) and they are rather slow responding. Does anyone know where I can buy the gas valve for this thing?

We went camping this weekend and our poor little parrot nearly froze (it was 46 low). He's a tropical bird and they are not used to those temps. We had someone to snuggle with, he didn't   .

[Bartman]

Wavery,

New to the forum. I recently bought a used Coleman Tacoma, my wife and I are truly enjoying it more than I thought we would.

Recently went camping at Ft. Davis State Park for a week. The heater started cycling during the 3rd night. It would attempt to light, couldn't would try a couple more times then give up but the fan never stopped running, most of the time.

Back at home I tackled the lil monster. I've got a background in HVAC so I was at least secure in my feelings that I should be able to figure out what was going on.

I did visit the Atwood website but there are no manuals, schematics etc available from them and won't be either until you complete their training.

After pulling the unit a few times and testing it in the garage I was ready to give up and call the local dealer.
I stepped back, took another analytical look at it. It was definitely electrical in nature. I traced back all the wiring to the component that it serviced or came from. I finally figured out that the sail switch is directly in line with the circuit board that houses the igniter.

I pulled the unit one more time, pulled the sail switch and hung it out the front of the heating unit.
After I put everything back together, fired the unit up and it did the exact same thing. I closed the sail switch and it ignited perfectly. I ran this type of test on it for over an hour to make sure that I wasn't getting a false positive, I wasn't.
Bear in mind that the sail switch tested good when I was testing everything.

Right now the sail switch has been taken out of the circuit until I can get a new one.

I hope this helps some.