Furnace Cold Air

[bipolarcoder]

We just pulled into our new campsite, hooked everything up and now the furnace rarely comes on and when it does it is blowing out cold air. I read that the 'sail switch' may need to be replaced or that it all needs to be reset. However I am unsure.

Can anyone help pinpoint the problem...

[jsb5717]

Many of us have been there. It helps to know exactly what you've got and exactly what it's doing.

Suburban or Atwood furnace?
When the thermostat is set to call for heat what happens and how long does it do it?

[Todd18302]

I have the same problem and mines an Atwood on a 2014 Passport. Any info helpful, thanks
T.S.
2014 Passport Ultralite
1992 Chevy C1500

[JRTJH]

Originally Posted by Todd18302

I have the same problem and mines an Atwood on a 2014 Passport. Any info helpful, thanks
T.S.
2014 Passport Ultralite
1992 Chevy C1500

What furnace you have is important, in explaining how to access the various components you need to check.

WHAT IS MUCH MORE IMPORTANT is what your furnace is doing. When you turn on the thermostat to call for heat, what does the furnace do?

Does the fan start to turn immediately, and then what?

You should hear a series of three clicks and the burner light. Do you hear that?

If you hear the clicks and the burner does not light, does it shut down then? or does it do that cycle two more times, about 30 seconds to 1 minute apart?

Then what? Does it shut down or does the fan continue to run, blowing "cold air" ???

It's important to know "What is happening and in what sequence"...

[bipolarcoder]

1) I don't know what type of heater it is. The only way to access it is is under the fridge. I don't have a book or anything and the outside only has an exhaust there isn't an access panel.

2) As soon as you turn it on it there are no clicks it waits a second or two then the blower motor comes on and it starts blowing cold air. I never hear an ignition.

[ChuckS]

If the furnace exhaust outside is one single port then you habe a Dometic Atwood series furnace.

… typically it would be an AFM 35 series

If you have two ports outside vertically for furnace then you have a Suburban unit

It child be an SF40, SF42, etc

[ChuckS]

https://www.trekwood.com/parts-searc...23+%2F+Keyword

Going back to your year the OEM furnace could have been Suburban SF30 series or Atwood 85 series

[JRTJH]

Originally Posted by bipolarcoder

1) I don't know what type of heater it is. The only way to access it is is under the fridge. I don't have a book or anything and the outside only has an exhaust there isn't an access panel.

2) As soon as you turn it on it there are no clicks it waits a second or two then the blower motor comes on and it starts blowing cold air. I never hear an ignition.

If you turn the thermostat to heat and the fan starts, but NOTHING else happens, on a 2011 trailer, I'd first suspect the sail switch is not closing. There are several reasons for that, but I'd suspect on a 12 year old trailer that there may be some lint, dog hair, or just plain dust that has clogged part of the vanes in the squirrel cage and the fan just can't move enough air to force the sail switch closed.

If NOTHING happens except for the fan to start, then shut down, I'd first start with a good cleaning of the fan squirrel cage and the interior of the furnace /duct connections as well as the compartment where the furnace is located, just to make sure it's relatively clean. Once that's done, then it's on to troubleshooting the cause.

[jsb5717]

I'd also suspect the sail switch. But it sounds like you'll have to pull the furnace out to troubleshoot. Once out I'd make sure that it runs all of its steps up to attempting to ignite before reinstalling it.

[bipolarcoder]

From my research I also suspected the sail switch. I just wasn't sure exactly where the thing is. I know the furnace is under my fridge but being a newbie I am nervous about pulling it out. I guess the only way to learn is to do though huh.

[bipolarcoder]

Single Port Exhuast my friend.

[jsb5717]

Yep, Atwood furnace. Make sure the propane is off before disconnecting. I turn it off then light the stove top until it dies to bleed off excess propane. Make sure to turn the stove off. Then proceed to pull the furnace.

It helps to take pictures from start to finish to help make sure you know where everything goes.

[wiredgeorge]

Youtube is your friend. I am not a furnace expert (never worked on one) but here is a video worth watching:

https://www.youtube.com/watch?v=7QDpMMxnwfc

[bipolarcoder]

This guy has some balls just cutting through the side of his RV. I don't have the nerve to do that.

[wiredgeorge]

Originally Posted by bipolarcoder

This guy has some balls just cutting through the side of his RV. I don't have the nerve to do that.

I cut a hole in the back of my camper for a weatherproof electrical plug connected to my microwave. I plug into a campground 110V outlet and do not have the microwave connected to the camper's electrical system (30A). I made another hole for a passthrough for wires for my WiFi and 4G antennas (have boosters for both). It isn't a big deal.

[440scout]

Originally Posted by bipolarcoder

This guy has some balls just cutting through the side of his RV. I don't have the nerve to do that.

The first time that furnace has to be pulled out for the sail switch is the time to mark where that access hole should go. At that point you can see if any wall studs, etc are in the way. What he did on that video is what Keystone should be doing at the factory. It only costs about $15 for the part and a little labor but its well worth it in the long run especially if you have dogs or cats aboard there will be lots of fur to clog up that sail switch

[bipolarcoder]

Yeah we had a tech come out and look at it and he thinks it is the gas valve that went bad and not the sail switch (which I already bought).

To get the furnace out you need to remove around 6 screws along with any hoses. Lift the furnace up and tilt to come up and over water lines and a grey line.