How Do I light My Gas Furnace?

[RickO]

We're in southern Minnesota for another few weeks and the nights are starting to get colder. Since we always do our darnedest to be OUT of cool weather, we're learning a few things about our coach. We're also limited to a 20 amp shore hook up at the present time so using the heat pump is out of the question.

The "rear furnace" which I always found to be a bit silly is actually really handy now. The thermostat is located behind the bulkhead door which can be closed to keep just the bedroom/bath warm all night with propane heat.

With the mornings being very cool, I wanted to use the "gas heat" feature on my basement Coleman True Air system. Setting the temp to desired setting and turning to "Gas Heat" results in the fan coming on for 30 seconds and then shutting off. My manual on this system is pathetic and says only to repeat these steps three times and then shut it down and get it serviced.

It sounds like it's just not lighting but I can't find any details on the process from here. Any ideas would be much appreciated.

Thanks,

Rick

[Beabop]

Suggest you call Winnebago tech support. They are very helpful.

[ichn2go]

First be sure the Propane is turned on at the tank. If it has been turned off, light one of the cook stove burners to start the flow of propane. If this doesn't work call Winnie..Good Luck

[TXiceman]

Turn on the valve at the tank and bleed the lines by lighting the stove burners. It may take 2, 3 or 4 attempts to get the furnace to light. The fan normally comes on first to clear the burner section of any trapped gas and then you should hear the igniter popping as it lights. If you can not hear the igniter, you may have a control board issue.

When it shuts down, the burner will shut off and then the fan will run for some time cooling the burner assembly

Ken

[RickO]

Thanks all. I've been using propane constantly for hot water, fridge, and the rear propane furnace I mentioned so the valve is turned on. The past couple of days have been so windy that I couldn't even listen for the igniters but today looks better so I'll check it out.

Thanks again....

rick

[TXiceman]

Also, some furnaces have another shut off valve at the furnace.

Ken

[two-niner]

Here I go again. The Mechanical Code requires a shutoff within three feet.
(arm's length)
Did you find one?

Kerry

[RickO]

Ok, I'm feeling a bit silly here because I should know this stuff but I've never had occassion to use the "gas heat" function on my Coleman heat pump before and I'm a bit perplexed.

I've located what I believe to be the gas furnace in a sealed section of my plumbing bay. The "hot" exhaust vent is there. When I turn the thermostat to "gas heat" I can feel cold air blowing out of this vent and I'm pretty sure I can hear the ignightor trying to light it over the noise of the fan. After about 30 seconds of failing to light it shuts down.

I can trace the gas line from the main tank to where it goes into the sealed compartment next to the exhaust fan and there is no shut off valve outside of the compartment. There are at lease 10 Torx fasteners holding the access plate in place and it's even got some weather proofing sealant on it so it's certainly not something they designed for easy, frequent access but I guess removing that is my next step.

Thanks again and stay tuned.

Rick

[RickO]

Update:

Well my call to Winnie Svc Admin didn't go as well as I had hoped. In the past, they first ask for my s/n and can address very specific issues with my coach. Today, the tech just asked what the problem was and I explained that my front gas furnace wouldn't light. His response was to tell me that I only had one gas furnace. He eventually pulled the drawings on my coach and confirmed that I in fact have two Suburban gas furnaces.

He went on to explain to me the lighting cycle the unit goes through but that special equipment is needed to test it. His only suggestion was for me to try to start the furnace with the engine running... which I'll try later but.....

During his explanation of what was happening, he told me low batteries could be the problem... but the rear unit works and I told him that specific gravity in all cells is good and my panel reads 13.2v. He dismissed that reading as the charger/inverter and explained that batteries themselves can never read >12.8v(?) I guess I learned something.

But, his last comment really caused me concern. While explaining that my 13.2v reading was coming from the inverter/charger he said I could turn off the Aux Battery switch to take my batteries completly out of service and the coach would still operate normally so long as shore power was connected. Last month I started what became a very long thread on this topic whick culminated in me calling Winnie and getting confirmation that the batteries were in series with the inverter/charger and turning off the Aux Batt switch would cause the entire coach to go black.

So, I'm glad this isn't a major issue and I can wait until November when I return to the area where I purchased to coach to get my dealer to repair it. Upon closer inspection, the only access to the furnace is via an inspection plate which is weather sealed quite tightly and clearly not intended to routine inspection.

Thanks to all for your suggestions and I'll update when my dealer has had a chance to take a look.

Rick

[phlemb]

I had the same problem last year , it was too cold for the heat pump so it switch over to the gas furnace. the furnace blower came on for approx 30 sec , tired to ignite but then shut down, after $350. it came down to a faulty sail switch (micro switch) it wasn't sending a "blower working" signal back to the board therefore shutting it all down. replaced switch, now all is good. hope this help

06 35a itasca sunrise

[Beabop]

WOW, he told you everything would work with the aux off. Should have gotten his name. Our 12 V was off last week, frige of course wouldn't work . I called Al at Winnie, told him no tripped breakers. He said could your aux bat switch be off? Well someone had bumped it and with it on ,all was right with the world.

[RickO]

Quote:

Originally Posted by phlemb I had the same problem last year , it was too cold for the heat pump so it switch over to the gas furnace. the furnace blower came on for approx 30 sec , tired to ignite but then shut down, after $350. it came down to a faulty sail switch (micro switch) it wasn't sending a "blower working" signal back to the board therefore shutting it all down. replaced switch, now all is good. hope this help 06 35a itasca sunrise

He did mention the sail switch. I trust my ext wty will cover this and I think we'll be ok until I can get my dealer to look at it. Especially considering the coach is nearly 4 years old and I've never used it!

Quote:

Originally Posted by Beabop WOW, he told you everything would work with the aux off. Should have gotten his name. Our 12 V was off last week, frige of course wouldn't work . I called Al at Winnie, told him no tripped breakers. He said could your aux bat switch be off? Well someone had bumped it and with it on ,all was right with the world.

Yep, he sure did but at that point I had lost all confidence in what he had to say and just wanted to get off the phone. He was polite and friendly but was clearly shocked (not surprised) that I actually had two Suburban furnaces. It was kind of downhill from there. I can't be sure but I think his name was Tom.

[Good man]

RickO,

Most any LP gas distributor will perform a courtesy safety check to determine if something needs attention. It is good business for them to promote the safety and reliability of LP gas. During this process, they will often successfully light the appliance.

You can also safely do certain things, as long as you do not defeat any safety controls.

Assuming that you have fuel in the tank, have a working gas leak detector which is allowing the gas to leave the tank, assuming that you have lit a gas burner on the stove to clear the lines and prove the emergency shut off is open, then,

During the follow procedure, leave storage bay doors open, the coach door open and several windows open to prevent the build up of gas. Have no engines running... neither the genset nor the MH engine. This almost certainly eliminates the potential for a flashover.

If you can look at the combustion chamber area of the furnace and locate the electric spark starter, you can verify whether it is sparking when the gas heat is demanded. This starter has an electrode in the area where the fuel enters the combustion chamber and it has an insulated, very flexible wire leading back to a valve mounted on the fuel line. This valve has wires leading back to the control module.

When the gas heat is demanded, if you do not hear loud repeated clicking and observe this spark, your control module, or other components may not be working. The is no harm in sharply bumping the control box with a closed fist to encourage it to signal the spark. Wait about 2 minutes between attempts to allow any fuel to dissipate.

You can repeat this process as many times as you like as long as you do not detect the smell of LP gas. This may clear any air out of the line leading to the furnace and eventually result in the furnace igniting.
Hope this helps... Be Careful.
Jim

[RVhauler]

If the electrical voltage is not sufficent then the fan will not turn fast enough and in turn prevent lighting of the furnace (ie: fore mentioned sail switch)