Furnace Will Not Light Up

mrgem · 09-09-2016, 06:41 PM

My brand new 2017 Palomini 180FB has a non-operative suburban furnace.

The blower comes on, the ignitor sparks, but the thing never lights. The first thing I checked was the gas supply. Propane tank was turned on - so that wasn't the problem. The stove top burners right above it work just fine. So gas is getting to the unit.

I turned it on by setting the T-stat. The fan comes on and and within a couple of seconds you can hear the gas valve click open. The ignitor start sparking (I can see it thru the little window), but after a couple of seconds, it quits trying. The unit waits a minute or so and then tries to light up again. Gas valve click, ignitor fires but the burner never lights. It tries to light it 3 times and then gives up -- with just the blower continuing to run.

I read in the furnace FAQ forum that another owner (of a much older trailer) had similar experience and ultimately figured out that the electrode on his ignitor was positioned wrong. That, after he was told by the dealer that his furnace worked fine on the test bench.

Before I drag it to an FR dealer, has anybody seen this before? I am hoping it is some kind of head-slapping rookie (this is my first RV) mistake -- but I don't think so.

Thanks for your help.

**Bama Rambler** · 09-09-2016, 08:37 PM

Sounds like you've done all the things you should have done. I don't think it's a rookie oversight.

Sure sounds like the furnace has a problem. Hopefully the service techs can figure it out and get it fixed permanently

mrgem · 09-10-2016, 08:28 AM

One thing I failed to mention...The trailer was prepped in a neighboring state at about 1200 ft above sea level. We live in the Rocky Mountains at 8200 feet. I know that when I bought a new furnace for my home last year, I had to have it jetted for high altitude use.

Could the difference in altitude be my problem? People from all over the country come here to camp every summer and I've not heard of problems with their propane appliances - but I am new to the hobby. I can tell you that the stovetop burns fine -- with a bright blue flame -- just like you'd want it to.

**Bama Rambler** · 09-10-2016, 09:09 PM

I don't think the altitude is causing your problem.

Even if it affected it, it wouldn't cause it not to light at all.

mrgem · 09-11-2016, 10:32 AM

Thanks. I didn't think altitude played a role, either...but wanted to be thorough in my analysis.

I've sent an email to Forest River' technical management asking them about it, and will hopefully get a response on Monday.

janice parker · 09-11-2016, 10:47 AM

We had more or less the same issue this past winter in Arizona - it turned out to be the "sail switch". No problem since.

**Flybob** · 09-11-2016, 10:49 AM

Check the shut off valve on the inside. Stranger things have happened. If you are hearing the gas solenoid click open, it is most likely not the sail switch as if that switch does not activate, it will not open the gas solenoid.

rvdoctor · 09-11-2016, 12:42 PM

If there is no other shutoff valve between the lp tank and furnace the gas pressure at the valve should be checked. Just because you hear the solenoid doesn't mean it is opening up. Also check the burner orifice to make sure no obstructions are present. As mentioned earlier it could also be the spark gap or cracked ceramic on the ignitor.

SimchaSabre · 09-11-2016, 12:46 PM

2 things could cause these symptoms...sail switch as just mentioned and hi temp switch. I've had a stuck sail switch before and also a bad hi-temp switch. Both are safety interlocks but also a potentiometer fault mode.

raspivey · 09-11-2016, 01:17 PM

I was testing mine before a trip a few weeks ago and the same thing happened. I had to cycle it on and off about a dozen times before it lit. I just assumed it was plumbed with a long section of line and was full of air. My water heater, fridge, and stove were all tested prior and it still didn't want to light. Once it lit I haven't had a problem since.

labcamper · 09-11-2016, 01:21 PM

Check the circuit breaker switch.

**Flybob** · 09-11-2016, 01:55 PM

The sail switch is a safety feature that will prevent the furnace from lighting ( opening propane valve and activating igniter ) if the fan is not moving sufficient air volume. If the propane solenoid is activating the sail switch is working.

mrgem · 09-11-2016, 02:07 PM

Thanks.

There does not appear to be any other shutoff between the tank and the furnace gas valve. When you watch the process with the front grill off the furnace, you can hear the gas valve click open and I would assume the gas should be flowing.

I've seen such behavior from home furnaces -- when the gas supply line has air pockets -- but after you repeat the process a few times -- and the air is bled out and they will usually light.

Following the click of the gas valve, the ignitor immediately starts arcing across the electrode gap -- very clearly visible through the window. Its as if no gas is getting through the valve to the burner.

It's important to note that there is NO smell of gas at the furnace during these tests, but you can turn on the stove burners right above the furnace and you get that mercaptan smell immediately. As I said earlier, the stove works fine.

As far as an obstructed orifice -- that could be -- but this is a brand new unit and the only firing of the furnace would have been at the factory or by the dealer's tech who went through it prior to delivery.

I'm reluctant to take the unit apart and inspect for things like a broken electrode on the ignitor or an obstructed orifice because the unit is new. Don't want to be accused of causing the problem myself.

Thanks again...This is quite the mystery.

mrgem · 09-11-2016, 02:12 PM

I thought of that -- but both the gas valve and the blower seem to be getting power. I would assume that all would be on the same breaker.

djemgoss · 09-11-2016, 11:09 PM

We bought a new 2016 Rockwood 21SS Roo this past March. I wanted to sleep in it in the driveway one night to check things out. The furnace quit in the middle of the night and would not re-light. It was to cold to stay in the camper so I went inside and would look at it in the morning. Had plenty of LP, the fuse were all good and no breakers were tripped. Call my dealer and he said to bring it in and they would look at it right away. They pulled the furnace out and put it on the techs bench and ran some test. The problem was a "High Limit Switch". They had one in stock and replaced it and reinstalled it in the camper and I was out of there in 1.5 hours max! Have not had to use it this summer but have turned it on a number of times to make sure its working!

mrgem · 09-12-2016, 08:51 AM

Excellent information. Thanks for the input.

mrgem · 09-12-2016, 03:55 PM

You will recall that I'd tried to get the furnace on my brand Palomini to work. I made at least a dozen attempts to light it up, but nothing seemed to work. Fan worked, ignitor worked, gas valve clicked open -- but no heat.

Well...Someone here suggested that I just keep trying. And I did. Finally after about 2 dozen attempts to start it, it mysteriously lit and made heat. I shut it down and restarted it. Worked like a charm. I went through this routine six times --and every time, it started just like it is supposed to.

I can only imagine that, as the poster suggested, there was a large air bubble in the gas supply line -- because it is working just fine now.

Thanks to all who offered their advice.

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