Attwood Furnace Problems - Montana Owners Club

jlb27537 · 02-08-2014, 03:50 PM

Hello Group. We have a Attwood Furmace that likes to work on it's own schedule. The furnace is under warranty, (bought 5/13) and a field service tech has stopped by twice and presently has a ignihter on order.

The problem is if the thermostat calls for heat, the furnace will not light every time. When it does not light it will show a 3 blink soft failure. At that time is goes into the 1 hour count down and then when that times out, if the thermostat is still calling for heat it will try and re-light.

When this issue started it seemed the furnace would work off the left tank better than the right. I removed the 30psi dropping regulator on the right tank and that seemed to fix it. For a couple of days. Then I considered I had gotten some bad LP. None of the other folks in the campground were having issues and by now it had become to where the problem was the same on both tanks.

We have checked the LP pressure at the test port on the gas valve and static it shows 11" with the furnace off and when burning shows 10".

All other LP appliances work just fine.

I have now discovered that if I leave it off all night, get up in the morning, turn it on, it will light and run till the thermostat is satisfied. This morning it took 40 minutes. It shut down. The thermostat called for heat, it ran for about 1 minute, got the 3 blink code and then tried to re-light every hour for 3 cycles. About noon it lit and ran for about 10 minutes as it should.

I have checked battery voltage and show 13.2 with it off at the board and 12.7 with the blower running. For a while I considered a low voltage issue and the converter or battery had to "catch up" so it could ignite, but the voltage at the board seemed constant.

We have swapped the OEM board with a Dinosaur when it would not light and no change.

I have talked with Attwood tech service and they are baffled and suggested the igniter, however they do not understand why it has to sit overnight or for 3-6 hours to relight again.

It has got to be something simple since when it does work it does as it should. My thinking about the tanks only working on one side, at that time I had not figured out the fact it only works once.

Guy's I need a new path to go down. I have not pulled the burner assy out yet, waiting on the ignihter to come in.

My electric bill will look like a college loan payment. But, I do not have to mess with the LP tanks much this winter.

Jim

Irlpguy · 02-08-2014, 05:11 PM

Jim I just experienced something similar with my furnace however it was affecting the stove as well.

Everything would work on one tank on the driver side, the other tank was just filled and the furnace would light and immediately go out and not relight. I had a new line made for the suspect tank to the red regulator with no difference. Took the gas line from the crossover pipe to the Auto regulator and found it had a small plastic washer type thing in the end with a spring behind it. I could not blow through this hose in either direction. I popped out the washer and the spring and another part came out which I lost on the ground. I could then blow through the hose and after re-installing the hose everything works great again.

Really crappy hoses used and I have no idea what this valve type thing was intended to do, but it works fine without it and I won't be putting an original hose back in there to replace it.

Just something you might check as it was allowing propane sometimes and not others, then a small amount and then none, all because of this hose.

pineranch · 02-08-2014, 11:16 PM

Ditto what Ed said.
Mike

bethandkevin · 02-09-2014, 02:00 AM

I'm just throwing an idea out there as I don't know how the auto regulator works. Could the washer and spring in the end of the hose cause the propane regulator to switch tanks when it sees a pressure differential and sucks the washer into the hose? If so, it would seem moisture could be an issue and freezing that valve. I've seen propane tanks come in to be filled while waiting for mine that had the valves left open. I always thought to myself this allowed moisture into the tank.

Irlpguy · 02-09-2014, 02:51 AM

I am not sure how the Auto regulator works either but one would think is is not reliant on external hoses or other parts. I think the washer and spring were intended to allow one way flow and not allow return gas to flow back to the tank. When it would not allow flow in either direction either it was flawed or there was not enough pressure to open the "valve" and perhaps I could not blow hard enough to overcome the springs pressure either.
Whatever, I know that was the problem and won't be replacing the hose with another one with that in the end of it.
I will confirm that with that tank empty there is no backflow from the full tank through the regulator.

All this is speculation as it may have nothing to do with the problem Jim has, but you never know.

richfaa · 02-09-2014, 03:58 AM

The OEM hoses are crap. Just go out and buy new ones or buy some for spares as you will sooner or later need one.Went through both OEM hoses on our 06 3400. Replaced with quality hoses and never had another problem. Have two hose spares on hand for this 13 3402.

jlb27537 · 02-09-2014, 05:12 AM

ED, are you talking about the valve in the plastic nut that screws onto the valve in tank. IF so, not being able to blow thru it is normal.

The valve in the plastic nut is a excess flow valve. If you hook up just the pig tail to a LP tank and turn on the tank valve there will be no or very little flow out of the hose. Turn off tank, remove pig tail, re-install pig tail and this time hold finger over end of hose and turn tank valve on. Now you will have flow from the hose. The valve in the plastic nut is looking for pressure on both sides of the valve for it to open.

It's purpose is to prevent/limit flow in case of a LP line failure.

I considered the LP flow thing, but when it lights and runs, it will for several minutes with out issue and when watching the stove top burner the flame color does not change.

Also when It does not light I have 10-11"WC of pressure when measured at the gas valve.

I am thinking sparky thingy has gone to lunch.

Jim

1retired06 · 02-09-2014, 06:34 AM

We experienced a similar recurring problem where the furnace would turn on but not light. I could find nothing wrong. I found that if I turned the furnace off and then adjusted the thermostat up to high temp, and turned back on it would ignite and then I would reset the temp to where we wanted it and it would then operate at the reset temp.

jlb27537 · 02-09-2014, 07:34 AM

Thanks Mike. The thermostat only connects the 2 blue wires together. They are either connected or they are not.

If the heater does not light on the first try, and the thermostat remains closed calling for heat, it will go into a soft limp mode and if the stat remains closed it will not try and relight for 1 hour.

If the thermostat is opened, turned off that will cause the board to reset. Then when the thermostat re-closes the furnace will then try to light with out the one hour delay.

Jim

Irlpguy · 02-09-2014, 04:54 PM

Jim the plastic end on the hose I am talking about is the hose from the end of the crossover pipe to the Auto regulator, the end with the plastic and spring assy was at the 3/8" pipe thread end that goes into the regulator.

I know what you are talking about and that I understand. I think you have a strictly furnace problem.

Good luck with the solution will be interested in the outcome.

jlb27537 · 02-10-2014, 03:23 AM

Ok Ed, Got it. The Service guy is supposed to come by this afternoon with a new igniter.

Question. Do you know why Keystone installed a 30psi regulator in the line of the right side tank while the left tank is connected directly to the crossover regulator?

I am wondering if it has something to do with some RVIA code about how long a LP line can be with high pressure on it?

Have you escaped the cold yet? Going to be 81 here today....

Thanks Jim

Irlpguy · 02-10-2014, 04:08 AM

Morning Jim

Oh yes we have escaped the cold weather at home, it is snowing there this morning but is supposed to warm up some. We are in Yuma for a couple of months.

I could only speculate as to the reasoning for the red 30 psi regulator, but would assume it has something to do with regulating that tanks output because of the distance to the Auto regulator. Some have removed it when they experienced problems with them, mine seems to be ok and since I replaced that one hose I have had no problems.

Seems your control board is working properly, when heat is called for the gas valve "should" open and the igniter "should" activate, if gas is present and you have ignition the flame sensor "should" signal the board that all is ok or if not, indicate the error code with the blinking LED. One thing for sure you must have fuel and ignition for the furnace to operate. Hope the igniter solves your problem.

Sounds like you don't need it much with 80 degree temps...

jlb27537 · 02-10-2014, 05:35 AM

Yea, last couple of nights/weeks have been quite cool/cold, today got both A/C's on. Got to Love S Texas.

Jim

Art-n-Marge · 02-10-2014, 05:51 AM

Silly jlb27537.... if it's cold, raise the temp on your A/C to something warmer. Temp-wise Southern California ain't so bad either, but probably costs more.

I've heard rumors of Propane shortages due to the extreme winters, but I'm guessing this is more a ploy just to raise prices so they don't have to bring them back down when the winter goes away. I haven't refilled any propane since November. Has anyone noticed?

jlb27537 · 02-10-2014, 06:13 AM

My neighbor was telling me he has filled his 40# bottles 9 times this winter @ about $30 each. I mentioned I had only used 2 30# bottles.

How is that possible? Is your Montana that well insulated. Nope, the LP furnace only works part time. But my electric bill was larger than his.

richfaa · 02-10-2014, 08:00 AM

propane went up here in Florida Piolt/Fj on this refill 3.699 per gallon. 25.54 for a fill with the Rv plus card.

rohrmann · 02-10-2014, 10:30 AM

As the discussion brought up questions about the red regulator on the tank opposite the switching regulator, I remembered seeing why it is needed in these two tank systems with the long pipe crossing to the other side of the trailer. No, it's not some RVIA or DOT requirement, but apparently basic propane technology. I copied this explanation from ForestRiverForums.com and was posted by one of their members a couple years ago--

The main reason for the regulator is to make sure that once the propane leaves the tank as a vapor that it stays a vapor. Propane regulators in trailers do not regulate liquid only vapor. If the regulator was not there the pressure in the hose would be the same as the tank. This could lead to the vapor condensening back into a liquid. With a reduction in the pressure from the regulator to the other side of the coach this will greatly reduce the possibility of the vapor in the crossover hose turning back into a liquid. This is all based on propanes vapor/pressure saturation points. the lower the pressure the lower the temperature to turn it back into a liquid.

8.1al · 02-10-2014, 11:33 AM

Thanks for a good explanation

jlb27537 · 02-10-2014, 01:52 PM

Ok, today the service guy installed a new igniter. The gap, per the service manual is 1/8" Mine was 5/32" when it was removed which is 1/32" too wide. I think. Like that would make a difference??

The service tech said he had never measured one, just eye balled it and installed it.

It lit 3 times, so we called it good. However, he said to call him in a week to see how it was doing before he sent in the warranty claim.

Was about 85 degrees when we fired it up. Front air on 72 and the furnace on 80.

I like the thought on the regulator, so I will re-install it tomorrow. However, I doubt this trailer will ever see below freezing weather.

Not sure it is fixed, but now I know how to get it apart.

To be continued......

Jim

paulinbaja · 03-09-2014, 10:46 AM

The parts in the line that escaped when the line was dismantled could be the parts that limit the gas leaking when the tank is pulled off for re-filling. The regulator performs this function but the line must also stay charged in order to prevent flame out at the next automatic changeover. If the heater is still under warranty have the service person replace it! Enough is enough.

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