Furnace problem - Montana Owners Club

sreigle · 10-22-2006, 02:42 PM

I'm going to go see our dealer in the morning since we're still under warranty but am wondering if anyone has a clue what the problem is with our furnace.

Saturday afternoon, three electric heaters running, inside temp is about 67 or 68. Thermostat (CCC) is set on 60, so the furnace should not run. We hear a swisha-swisha-swisha sound that sounds a lot like the washing machine during an agitation cycle. I tracked it down, inside and out, to the furnace.

I changed the thermostat to 75 to see if the furnace would run. It comes on but blows cold air. And cold exhaust outside. Not igniting propane, in other words.

The furnace shut off. In 20 or 30 minutes it fires up again, thermostat still at 75. Cold air, cold exhaust. Dropped the thermostat back to 60. Furnace is still running 10 minutes later. Still cold. Turned the thermostat to Off (not the off switch, just the Off mode). Furnace still runs and runs and runs.

So I pulled the fuse on the fuse panel in the bathroom. Furnace stops. Put the fuse in, swisha-swisha-swisha. Pulled the fuse and left it out.

We're fine on inside temperature. No hard freezes yet. Lows the past few nights have been 31 to 33. Same tonight. Then a bit warmer. So we have some time.

The furnace did work fine but had not been used in a few days. I pulled the outside cover and could see no problem. No obstructions. No insects.

Does this sound like a bad control board?

hazmic · 10-22-2006, 02:51 PM

Just my guess but I would bet you are 100% right. Could also be the sail switch if you could by pass it but still being under warranty,I would let them fix it,so they can't say you did it. Good luck and keep us informed.

noneck · 10-22-2006, 03:01 PM

Hi Steve,
That sucks...so no odor of propane or sounds of ingnitor?....maybe that was your reference to swisha?? Typically for devices of this sort there is a timer that gives up to stop propane flow due to fault in ignition... air flow is maintained to sweep out burnt or unburnt fuel so things don't go boom. Yes, leave fuse out...have someone with correct diagnostics tools check it out as your warranty will cover you.
Chuck

sreigle · 10-22-2006, 03:11 PM

Thanks guys. No fumes, no odor of propane. I wish I had pulled the outside cover when it was running cold. The fan works, it did blow cold air. The swisha didn't sound like an ignition attempt to me. It did not sound like the water heater trying to ignite. Not a snapping sound. It sounded more like a rotational sound. But maybe it was trying to ignite. The sail switch is a possibility. But as noted, I'll talk with our dealer tomorrow. I kinda doubt they can send anyone out. We're set up for a two month stay so will have to disconnect everything but heat is important so we'll do it.

snfexpress · 10-22-2006, 03:22 PM

Steve,

I'm having the same problem. I tried a universal circuit board, but they don't work in the 8535-IV furnace, so I am waiting until tomorrow to order a new board from dealer (under warranty).

I noticed you have a 3400, although it is a 2007. Mine is a 2006, but the configuration should be the same. You actually have to take out the furnace to replace the circuit board. Keystone "redesigned" the furnace to sit in the area between the basement inside particle board and the rear of the kitchen pantry. The bad thing is that I had to cut a hole in the back of my pantry so that I could get at the screw holding down the furnace on the side facing the rear of the pantry wall (doubled wall, in my case).

My solution is that I am going to cut a large oblong hole in the side of my 5er and mount the furnace the way it should have been mounted: with a cover on the outside allowing easy entry to replace the circuit board, sail switch, fan and limit switch.

The circuit board has the fan circuit on it, so make sure you get the model number from your particular furnace - it will be on the fan housing, inside the furnace.

We're in Beaver, Utah, with overnight lows of 29 degrees. No hard freezes in the forecast, but I have at least two more nights without a furnace - will order the part Monday morning, but won't have it until at least Tuesday sometime.

While the boards are about 200 hundred bucks, I am going to get a spare so that if this happens again, I can replace the board in less than 5 minutes. It took me about an hour to get the furnace out of the cramped space!

I hope your configuration is better than mine. I would like to know how it all works out for you.

noneck · 10-22-2006, 03:29 PM

Hi Steve,
This would make me nuts if I was in your shoes...the propane odor should only be detected at the exhaust port during ignition attempt, prior to "time-out". If during furnace initial turn-on you do not smell any at the exhaust then it sounds like the LP inlet solenoid is not being opened...you should beable to measure the voltage to this valve if its accessable? Just an unretired...concerned wannabe fulltimer...but have three grown kids still in college.
Good luck, and if this is outside your capabilities...leave it for the experts.
Chuck

Hemlockusa · 10-22-2006, 03:43 PM

Steve - try lighting your water heater on the GAS... or stove top... Prehaps the whole problem is in the DUAL VALVE for the two gas bottles. sounds like your not getting the gas to ignite. If your gas side of the water heater also fails to ignite I would say it is in the Dual Valve Switch (thing a ma jig) on the bottles. KANSAS THINKING HERE.. I could be way off base.
Nice to hear your still warm even though no furnace, if you were closer I would come over and help. OH in a Pinch Vicki's hair dryer will also warm you.. ha ha Safe Travels you two John

noneck · 10-22-2006, 04:27 PM

Ahhhh, John,
I assumed Steve has checked that LP was alive! You could be on to something here, if stove doesn't light, Hot water not working on LP....good thoughts!
Chuck

snfexpress · 10-22-2006, 04:40 PM

Just for more info, the circuit board operates the propane inlet switch. If the board is malfunctioning, then it won't allow the inlet switch to open. You'll hear the igniter, but no ignition.

JH Sechelt · 10-22-2006, 08:22 PM

I'm with John, Doesn't sound like the furnace is getting fuel. A while back ours did the same thing.
One propane tank was empty, and the switch over valve wouldn't supply enough propane for the furnace to work. The stove would light OK on the second tank but when the furnace tried to light, the little indicator above the switch over valve would go into the red. Fan would blow but no heat. Moved tanks around and furnace worked fine. took everything apart & played with switch over valve and all seems to work OK for now. Don't really know why. let us know what the dealer finds.

J&D

Wrenchtraveller · 10-23-2006, 02:39 AM

I was having trouble with my furnace the other day and then I noticed I had the mode set to cool on my thermostat. I set the mode to heat and all is fine now,

I hope your problem is minor and gets fixed quick. Take care.

sreigle · 10-23-2006, 02:34 PM

Thanks for all the suggestions. Propane was the first thing I checked. Stove and water heater both work fine on LP.

Our dealer arranged with a mobile service to come out. Trouble is, he's booked for 3 1/2 weeks. But, being it's the furnace in October he said he'll get here soon as he can and that the weather forecast for the next ten days is favorable. He's right. 31 tonight, then lows in the upper 40's and low 50's (back to normal). If he gets a cancellation or gets done early or the weather threatens to turn bad then he'll get here.

Meanwhile, the dealer asked me if I'd like to try a new thermostat. It's the CCC thermostat (not the remote type) and is a very easy swap so I said 'sure.' Unfortunately, the new thermostat just gives an "EE" error message. The old one still works fine from what I can tell.

Besides the furnace blowing cold air and cold exhaust (meaning no propane ignition) it still makes that strange noise and turns on the fan when it shouldn't and won't shut it off when it should. Since it's only just under two months old I'm going to let the service guy deal with it. I don't want to do anything that could potentialy void the warranty.

JH, the one thing different since we used the furnace when it was working is I've attached to a 100lb propane bottle. External. I didn't check to see if the flag goes up when the furnace tries to light off. I will check that. Thanks.

sreigle · 10-23-2006, 02:40 PM

This is strange. I set the thermostat to fire up the furnace and check what JH suggested. At first we had cold air blowing for longer than I think it should. I went outside to flip the regulator and could hear the burner going in the furnace. Checked and the exhaust was hot. The furnace is working. I think I'm not going to cancel the service guy until I know it's not just an intermittent situation.

Thanks for all the suggestions.

bsmeaton · 10-23-2006, 02:43 PM

Steve,

Glad you got heat back! Did the noise go away as well?
Intermittent is some times harder to fix than just plain broke.

Brad

Charlie · 10-23-2006, 03:46 PM

Steve-
Could there be a difference is regulator type and pressures? Our first trip out we had a problem with oil in the crossover pipe plugging the original regulator and I tried to use a different style regulator as a temporary fix and it would not fire the furance but it would fire the water heater and stove. I had to make a 100 mile round trip that day to find a OEM replacement regulator and it worked.

Glad that you have it working for now, think that it to be a wise decision to have it checked.

w4nfr · 10-23-2006, 04:06 PM

I do not know if anybody mentioned this, but check your limit termo switch or switches. There is one typically in front when you take the intake grill off. I had trouble with the furnace ignition and found the limit switch to be defective. I clipped a jumper wire across the limit switch and it worked fine until I found the proper replacement.
Apparently, this switch must be normally closed for the furnace to ignite and operate properly, but the switch opens if things get too hot.

sreigle · 10-23-2006, 05:12 PM

Thanks.

I now suspect that small red regulator on the line from the bottle on the opposite side from the regulator.

The furnace came on awhile ago and worked fine. I went upstairs and saw this time the red light is flashing. That's the light from my remote propane out indicator that flashes when the red flag goes up on the regulator. Same symptom JH noted. I went out and flipped the lever to use the bottle by the regulator and the light went out and green flag came back on the regulator and the furnace ws running fine. Flipped it back and forth. Same thing. Red flag from one side, not from the other.

The side away from the regulator is where I've connected the 100 lb external propane bottle. That's the side with the little red regulator. When the main regulator points to that side is when the red flag goes up. But it goes up only when the furnace is running. The external connector was there back before the furnace problem started but it was not connected to a bottle at that time.

I don't see any kinks in the propane lines or any other visible obstructions.

I doublechecked the water heater and stove. Both are fine. And the furnace now is working fine, too. I'll go talk to our dealer in the morning and maybe get one of those regulators from them. Meanwhile I flipped the regulator to use our onboard bottle until this is resolved.

Does anyone see any other solution other than that little red regulator?

CRUZIN 2 · 10-23-2006, 05:55 PM

Steve

When we were in Goshen they replaced our regulator, after two years old, it was full of oil (like Charlie's)also. It was cutting down the pressure, when they checked it out. I was having problems with the hot water heater not burning right. This seems to be a common problem with the regulator's. I should add that the furnace and stove worked OK.

Just my two cents worth. Larry

JH Sechelt · 10-23-2006, 07:40 PM

Hi Steve,

Glad you got it working. I took all my propane fittings between the tanks apart and blew out the cross over pipe with air, and never did find any thing obviously wrong with anything. I played with the switch over valve for about a half an hour, turning it back and forth and finally the tank on the road side started to work. Obviously something is wrong with the switch over valve, but for now (or at least the last time we used the furnace it worked). I suspect we will need to change the valve before long. We should do it before the end of Nov as our year will be up. Oh well, dealer is too far away & I don't suppose the valve cost that much anyways.

J&D

Wrenchtraveller · 10-24-2006, 02:35 AM

It makes you wonder if the automatic switch over valve can fail intermittently because last year I woke up in the morning to a cold trailer. The one tank had run out and the furnace had stopped. I could not get the propane to the furnace from the other tank no matter what I did. I moved the full tank around to the other side and the furnace fired up fine.
I filled the empty tank and for the rest of the trip we used at least 6 bottles of propane and never had a problem with the automatic switch over. I had forgotton about the incident until reading this post. It was below freezing when I had the problem. After that we had cool weather but no more frost. Is it possible the system can freeze up?

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