Suburban Furnace Problem

rturriff7 · 05-16-2012, 08:14 PM

When I turn my thermostat up, I hear the click in the thermostat and from the furnace but nothing happens. I can't get ignition or the furnace fan to come on. All other gas appliances seem to work fine (stoves, hot water tank). Any ideas?

rhagfo · 05-16-2012, 09:54 PM

Quote:

Originally Posted by rturriff7

When I turn my thermostat up, I hear the click in the thermostat and from the furnace but nothing happens. I can't get ignition or the furnace fan to come on. All other gas appliances seem to work fine (stoves, hot water tank). Any ideas?

Check the wiring from T-stat to furnace, may have a broken wire, the next possibility is a bad control board.

rturriff7 · 05-17-2012, 07:44 AM

I can't see a broken wire at the furnace end or at the thermostat but in between the two, well who knows. But I do get the click sound at the furnace. Would that mean that the electricity is fine?

Ruffus · 05-17-2012, 08:06 AM

You could possibly have air in your line too. Mine did this and I found that when I lit the stove it would come on so I thought all was working except the heater, then the burner would slowly die out. Mine was a propane bottle that had a bad safety valve on it. I found that if I let it sit for 30 minutes after slowly turning it on everything worked fine. I hope you get it figured out.

**hankpage** · 05-17-2012, 10:47 AM

If your fan does not come on, the problem is not gas related. The fan should run for awhile before you get ignition. (Purge cycle) Check your fuses and the wire-nuts on the wires so neatly secured

on top of the furnace itself. I would suspect a problem with the fan or control module. ( What position is the fan switch on the thermostat in????? )

rhagfo · 05-17-2012, 11:16 AM

Quote:

Originally Posted by hankpage

If your fan does not come on, the problem is not gas related. The fan should run for awhile before you get ignition. (Purge cycle) Check your fuses and the wire-nuts on the wires so neatly secured

on top of the furnace itself. I would suspect a problem with the fan or control module. ( What position is the fan switch on the thermostat in????? )

Oh how we miss the simplest things in trouble shooting!

**hankpage** · 05-17-2012, 12:03 PM

Quote:

Originally Posted by rhagfo

Oh how we miss the simplest things in trouble shooting!

Give an old guy a break .... the brain got there eventually.

rturriff7 · 05-18-2012, 07:15 AM

Doesn't seem to matter which position the fan switch is in. Have tried on and auto both high and low. The connections near the furnace seem ok. And the fuse is fine too.

rhagfo · 05-19-2012, 10:56 AM

Quote:

Originally Posted by rturriff7

Doesn't seem to matter which position the fan switch is in. Have tried on and auto both high and low. The connections near the furnace seem ok. And the fuse is fine too.

Not sure, but I think Hankpage was referring to the Heat/Cool switch. Furnace won't come on in the cool position.

PS: To Hankpage, the switch was the step we all missed earlier! Good Call!

rturriff7 · 05-28-2012, 05:53 AM

Well after 2 nights of freezing the furnace randomly turned on in the middle of the third night and has worked ever since. No idea why. Now I'm sure I won't be able to get it fixed as the dealer won't be able to reproduce the problem. Hmmmm.

rhagfo · 05-28-2012, 06:16 AM

I stand by the second part of my 1st post, bad control board. Mine will sometimes not come on, simply flipping the Heat/off/cool switch to off then back to heat solves the issue. This really points to the control board.

rturriff7 · 06-02-2012, 02:23 PM

Excuse my ignorance but...

Is the control board part of the furnace or part of the thermostat?

Update...

Went out again last night and got setup. Furnace won't work again. I left the switch in the on position and turned the heat up. At some point in the night it started up again.

rhagfo · 06-04-2012, 06:32 PM

Control board is part of the furnace. It controls the furnace once the t-stat calls for heat, once the T-stat indicates we have enough heat it controls the shut down of the furnace.

Jess6092 · 12-28-2012, 10:40 AM

I am having this same issue right now with my furnace. Where would one find the control board? Is it replacable or does it require a repairman?

**JRTJH** · 12-30-2012, 07:57 AM

The control board is found inside the furnace. Dig out your owner's manual for the furnace and you'll find it in the parts breakdown.

The control board is user replaceable, but if you don't have basic tools and mechanical ability, I wouldn't attempt it this time of year. If you mess something up, it's a cold night until the repairman can get there. However, if you're mechanically inclined, it's not really difficult.

As for getting a new board, they are available at most RV service centers, but there are "aftermarket" boards, DINOSAUR Electronics makes a board that is much more reliable than the factory boards. You can find factory information about them here:

http://www.dinosaurelectronics.com/Ignitor_boards.htm

They are sold at a number of RV dealerships, but you can get them online here:

http://www.americanrvcompany.com/Uni...rds_c_375.html

If you don't know what you need, get the furnace information from the decal on the furnace and call them at: 626 513 4777.

This is just one source for the igniter board, there are a number of others available if you do a Google search for "furnace ignitor board" or for "Dinasour ignitor board"

I've used Dinasour products since an old instamatic RV6 refrigerator bit the dust in 1975. Being an airplane avionics repairman in an earlier life, I appreciate the way they build their circuit boards. Much sturdier, better soldering and they are sealed from the weather and moisture, something you seldom find from the original factory. And, for the record, I have no interest in the company, in fact my only interest is from good results when using their products.

rhagfo, Your problem sounds like the fan relay on the control board sticking. I'm not sure if a well placed screwdriver handle tapped against the relay housing might help or not, but it sounds like your fan relay is energizing, then sticking and not supplying power to continue the lighting sequence. When you turn power off and then back on, it resets the relay and it'll work a few times before it sticks again. Might help to remember the old airplane repair motto: "If it doesn't work and you can't fix it, get a bigger hammer" (of course you have to be able to camoflage the dent marks afterward <wink>)

Just for "grins" before you go doing a lot of changing boards, etc. One of the most common problems with furnaces not lighting is either dirt in the intake vent (cobwebs, dirt dauber nests, etc) or carbon soot on the igniter pins. Crawl down under your cabinet, take the cover off the furnace and use an old toothbrush to clean the pins on the igniter. It's the part that looks like an old spark plug wire. then use an air compressor and/or a wet dry vac and clean the exhaust vent on the outside of the RV. An old bottle brush will help get anything out that seems stuck. If those two things don't help, then start looking at the control board. Usually the reason for soot on the igniter pins is lack of oxygen from a plugged vent.

Jess6092 · 01-17-2013, 07:30 AM

Thanks for the tip. I will try cleaning everything out well before dealing with the repair man. Been using space heaters that work pretty well, so haven't done much about the original funace yet.

Jess6092 · 01-30-2013, 10:32 AM

Just FFI, our problem turned out to be the control board.

wowchad · 01-03-2015, 08:08 PM

I'm going to tag onto this thread since its applicable to my issue.
I read this thread and it was helpful, then I found a YouTube video that showed how to remove the unit but I cannot seem to figure out how to disconnect the wires. It's in s 2009 Outback where there's no access from the outside, it's has to come out through the inside.
Can anyone shed some light on how to disconnect these wires once I've wiggled the unit loose from the outter exhaust cover?
This is the You Tube video that showed how to remove my style heater from the inside

https://m.youtube.com/watch?v=c5e5gZpvtb0

**chuckster57** · 01-03-2015, 09:13 PM

Quote:

Originally Posted by wowchad

I'm going to tag onto this thread since its applicable to my issue.
I read this thread and it was helpful, then I found a YouTube video that showed how to remove the unit but I cannot seem to figure out how to disconnect the wires. It's in s 2009 Outback where there's no access from the outside, it's has to come out through the inside.
Can anyone shed some light on how to disconnect these wires once I've wiggled the unit loose from the outter exhaust cover?

If you remove the return grille, then you should see the gas line at the front right corner. TURN OFF the propane before you remove the line. That front plate is the cover and should take a couple of screws to remove. Once that cover is off, there should be a single screw in the center holding the whole unit in the case. As a rule there should be enough wiring to pull the unit out and at that point you will be able to see where they attach.

wowchad · 01-04-2015, 07:47 AM

Yeah I got everything disconnected and wiggled the whole unit loose from the outside fittings (vent) but I cannot pull it out because the wires are taunt. I tried to turn it sideways as much as possible to access the connectors but cannot reach them. They must be inside, right on control board and I just can't get my hand to the dang thing. Seems like there's a panel or sheet metal still in the way.
I even pulled the refer cover to see if I could pickup some slack from above where the wires come from but no dice. I'm truly stuck and using electric heaters which freaks me out some!

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