Furnace Problems

[rickfox]

They say timing is everthing, and sometimes the timing is bad.

We have spent the last 2 weeks in the Rio Grande Valley, hoping to enjoy the good weather. Wrong. It has been un seasonabley cold. And the furnace has now been down since 3 days ago.

I'm hoping for some help from the MOC braintrust.

The furnace fan comes on, and cycles 3 times trying to get the LP to ignite, and then goes back off. There is an LED on the control board that blinks with 3 flashes. The Atwood furnace customer support guy says this means the system has progressed to the lock-out mode, having passed the air circulation mode, the ignition mode, and passed the board test. According to him, this condition often means that the LP pressure is low (checked - is OK).

It could also mean that the ignition electrode is not functioning properly. Supposedly after the LP valve is electronically turned on (I can hear the click) the electrode spark starts click/click/clicking and the LP/air mixture starts burning. I can not hear this clicking noise - but the CS man says that depending on how the furnace is mounted, I might not be able to hear it.

Can any of you out there with a 3400 hear this clicking sound when your furnace starts? Also, has anyone done any work on their furnace? Unfortunately, it appears that Keystone did not consider the ease of working on the unit, as there apparently are no access panels, and access to the innards appears to be on the side that is not accessable unless the furnace is actually removed from its mounting location.

[minkid]

Hi rickox,I agree you have to pull most furnaces in these things to work on them.Another possability is you could have a sticky or bad gas valve,have seen that happen when working on some of these things.It is also possible the sail switch is dirty or stuck. Hope this helps ,good luck.

[Ozz]

Try cutting the power completely to the unit, and then turn it back on.
Snfexpress had the same problem, had to cut an access hole to get to it. Bummer.
Where are you?

[rickfox]

Ozz,

I noticed you were at South Padre Is. We are in Mercedes, TX. We have tried about everything. I have turned the power off at the furnace (there is a power switch on top of the unit) turned off the thermostat, and removed the fuse.

According to Atwood CS, the flashing LED on the control board indicates the sail switch, overload switch, and airlow in general is OK. When the gas valve click open, I can smell the LP in the furnace exhaust air. But I can not hear if the ignition electrode is sparking. I powered up the hot water heater burner and can hear its spark electrode. So, I am currently thinking the furnace electrode is dirty or nonfunctional.

But, as I mentioned, it appears that this part is located on the back side of the unit and perhaps not accessable without removing the furnace.

By the way Ozz, my cabinet wall panel just to the left of the oven also partially busted out at the bottom. The small vertical support board (the one that had a knot hole in yours I believe) was not screwed to the outside wall. The only thing holding panel in place were its connection to the small support board that was screwed to the floor at the bottom of the panel. The panel broke away from this board at the bottom right where the panel comes into contact to the outside wall and the floor.

My fix was to install a taller base board that was firmly nailed to the bottom board, and to install a support board that connected horizontally from the frame around the hot water access hole to the underside of the shelf bottom that is accessed from the living room. I would have liked to do more work inside but could not gain access without tearing things further apart.

MONTANA NEEDS TO FIX THIS PANEL PROBLEM AS I BELEIVE IT WILL START EFFECTING ALOT OF 3400'S

[Ozzie]

I believe I read here of others in the same predicament...their fix was to rap on it to clean it off. Sounds barbaric, but it worked for them.

[Briarglenn]

rickfox,

I've had the same problem with my furnace since Christmas Eve. Fortunately, we had an appointment with a service department in Grants Pass, Or on the 27th of Dec. My circuit board was loose when I looked at it on Christmas Eve, but I could not get it to work.

The dealer cleaned the contact points and that seemed to correct the problem. The mechanic said that if that didn't do it then I needed a new circuit board. Well that evening it didn't work on the first try, but did then after and with no problem until yesterday when it rained here in Arizona.

It quit working yesterday afternoon, and then after we had gotten the ceramic heaters out and working it started right up. Not so this morning and now I've got to run through the same things you are doing.

I will let you know how my progress goes

[Ozz]

I would 'Bet the farm' on a bad circuit board. OK, just the barn. Might be something in between the electrode and the ground, but doubt it.
I have mine out of my furnace right now, I'm wiring a switch so the fan can run independent of the thermostat
Thanks for the tip on the wall, I will let the dealer take care of it, they know I have a list for them.

[Briarglenn]

rickfox,

I pulled my circuit board and only found dust, quite a bit considering its location. Anyway, blew it off with compressed air and took a Q-Tip to it then re-installed it. It works fine now. I'm thinking static electricity somehow connected to damp air, but then again I am not an electrician so I'm just guessing.

Hope this helps.

[CRUZIN 2]

All

Thanks to all for the info. and what to look for if a person would have a problem.

Larry & LaVonne

[sreigle]

We had the same problem this last winter. The control board was the problem. It was badly corroded despite being a new furnace. I could hear it click, trying to light, but it would not light. Eventually it quit trying. Every time I tried it, same thing.

[snfexpress]

Sounds like the electrode, to me. It's real hard to replace, but if it isn't at the proper gap from ground, it won't spark and ignite the propane. I believe your board is okay. I have become a real expert on furnaces, having spent 3 whole days on it. I took it out, replaced the circuit board, checked the sail switch and replaced the electrode. No problems, now.

Call Atwood, have them send you a new circuit board and electrode. You will want the circuit board, even though you have to pay for it, because if you get a good electrical spike, your board may fry and you don't want to have to wait for a new one.

As for the electrode, since you have a 2006, like me, you need to completely remove the furnace (even to replace the board). Take the screws out of the outside vent and remove the vent. By the way, when you bench test the furnace, you have to put the vent tube back in the furnace, or it will not light. I learned this the hard way. The vent tube is about 12 inches long, from what I remember.

There are some screws on the forward side of the furnace connecting the tabs to the trailer wall. There are 2 large screws holding it down to the floor (where the lower level furnace vent is). I had to cut a hole in my pantry to get to the inside screw because one of the old world craftsmen angled the screw from the pantry (not installed at the time) towards the front of the trailer, therefore not permitting any type of contorting to get the screw out. Finally, turn off your propane and disconnect the fitting to the furnace.

Remove the hose vents - there is a screw in the metal flashing and then turn the flashing until it removes - you may not have to remove the vent hose.

Now that the unit is out, sit it on a bench, with the circuit board side up (like it sits in the 5er). Down at the bottom, behind the propane valve, you'll see the electrode - it has two screws. I used an articulating nut driver to remove the screws. Then I spend about 30 minutes maneuvering the electrode around to get it out. Once I got it out (without removing the propane valve because I was unsure how it disassembled), I knew the new one would go in. Spent another 30 minutes or so and cutting up my hand and got the new one in. Now, NO PROBLEMS!

As I mentioned, though, I put the furnace back in place without screwing it down and connected the propane to test it. It wouldn't work. Called Atwood and they told me the furnace exhaust tube MUST be inserted into the furnace to allow the furnace to light.

If you have more questions, please don't hesitate to ask. I will help in any way I can.

[dsprik]

I hope this doesn't take a wrong turn - maybe should start another thread, but what's the problem with the cupboard wall to the left of the stove in my 3400??? I just looked at it, and while it is intact, it is bowed out badly. Also, just started getting a cracking noise two days ago from the floor when I step on the floor right next to that wall.

Is there some maintainence schedule for that board in that furnace?

[OntMont]

Lots of good suggestions here, but in keeping with the KISS priciple, make sure your gas supply is OK before going to a lot of trouble working on the furnace. The furnace takes a lot more gas than the other appliances, so it may not run while other appliances do. Make sure that the safety devices built into the propane tanks have not actuated, cutting the propane flow to a minimum. If you have not already done so, close the tank valves, then re-open them just a crack to let the gas pressure build up, before opening the valves fully. Maybe a freindly neighbour would let you try their tank, just to make sure that the problem in not in the tank, rather than the furnace.

If the problem does prove to be with the circuit board, I have read that there are after market boards that are supposed to be more rugged than the OEM board. Dinosaur is one brand name.

(PS we are in Mission).

[Ozz]

Yes, Rickfox, you and I have the same problem. If any other members have it, please let us know. I'll start another thread on it.
Rickfox, have you fixed the furnace yet?
Ozz

[rickfox]

As Micheal mentioned, it is a real bear getting the furnace out. I have gone down the same path as he. I was able to get the back floor mount screw out because it was angled toward the rear of the trailer so did not have to cut a hole in the pantry. Also managed to get the electrode out with great difficulty. Neither Atwood nor Keystone seem to think much about maintenance and repair capabilities. My guess is that the electrode is fine, and the wiring looks good.

I will clean it up some before I reinstall it, but will be surprised if things work. Although the circuit board appears to be clean with no visual problems, I won't be surprised if it is the problem - even though Atwood Customer Service says they do not believe it is.

Will know more later today after I get it back together.

[Ozz]

Good luck Rick, I wish we were closer, I'd roll up my sleeves and help you.

[jerryb]

We had that problem last year, it was a poor ground wire. The repair man found an intermitant ground, couldn't find a bad connection, so drilled a hole in the floor and ran a new ground wire to the frame.
Another cause could be low voltage, the furnace is 12 volt and will not fire at anything under.

[rickfox]

Good news and bad news! The good news - After cleaning the electrode and putting everything back together, all is working fine. The bad news is that it is a pain the the a-- pulling the furnace out far enough to work on, , and reinstgetting the electrode out to clean off, and reinstalling everything. I won't be surprised if this is a continuing maintenance issue. So, I made a few small changes in the re-install that should make things a little easier the next time I have to jerk it out for cleaning. Now I can hear the electrode sparking, and then the fire starts up.

Atwood was correct. It was the electrode that needed cleaning.

[Okie Guy]

Rickfox I am glad things finally started going your way and you have heat again.

[Ozz]

Yeaaaaaa!!
Glad it's fixed.