Furnace Not Working

[scroon]

First boondocking trip had problems with the batteries not holding a charge using the generator. Now went to put the furnace on the fan comes on for a few seconds and then shuts off it's blowing cold air and i have plenty of propane in the tanks

[CRH]

Sounds like a problem with the sail switch

[scroon]

What​ is that

[CRH]

It's switch that closes right after the blower comes on. It closing completes the ignition circuit. If it doesn't close, your fan will stop. Weak batteries can keep it from closing.

[OTRA15]

Welcome to the forum!

The sail switch is a small physical device which sits inside the discharge duct of a hot air furnace, and is actually a little "sail in the wind" -- a physical plate which the moving hot air causes to "sail" which completes the furnace's "all systems go" circuit. It is designed to prevent overheating if the blower fan does not work right, and the furnace ignites but the discharge air does not flow correctly.

If you have air moving, the problem may indeed be your sail switch not signaling that the discharged hot air is moving correctly.

If you supply more details, folks here could consider other possible problems:

-- bad ignitor or pilot light
-- loose/bad 12v connections
-- furnace circuit board bad
-- battery voltage low
-- propane regulator bad
-- etc.

What year and model do you have, and does the furnace have a pilot light, or an electronic ignitor? Can you hear the ignitor clicking as the furnace tries to start? What battery voltage does your monitor panel report? You refer to problems charging with the gen. If your battery voltage is below 12.2-12.3 [standard flooded cell batteries], they are below 50% capacity. In this case, the furnace circuit board may refuse to initiate the start-up IMO. How old are your batteries, and have you tested each cell with a hydrometer to confirm the batteries are OK?

You report having propane in the tanks, but do all of your other propane appliances work correctly including the cooktop and water heater?

More details please!

Thanks,

Peter

Originally Posted by scroon

First boondocking trip had problems with the batteries not holding a charge using the generator. Now went to put the furnace on the fan comes on for a few seconds and then shuts off it's blowing cold air and i have plenty of propane in the tanks

[scroon]

The furnace won't come on even when plugged in to a generato all the propane appliances work the battery voltage is low but I'm plugged in to a generator it's 2017 25 fc

[scroon]

The voltage is 13.6 when plugged in to a generator

[glcmranger]

It's your batteries. It doesn't matter if you'r hooked up to Generator or Shore Power, which, goes through your converter. The furnace needs enough DC power from your batteries--which is minimum of 12.2. I have the EXACT same thing happen to me. Get rid of that single stage Converter and replace the batteries. Search on the forum on this topic...... plenty of information.

[scroon]

Glm was your thermostat acting wacky also having to hit the buttons on it a few times to make it respond. This is the first trip with a brand new trailer

[Lily&Me]

Be sure to call the service department at your dealer, also take a look at your owners manual under trouble shooting for your furnace.

If you have a brand new trailer, I would advise against trying to fix or replace something yourself.

Not only are you under warranty, but you may void something by tampering.

There is a learning curve with a new rig. We had the service guy on speed dial the first few months we had ours.

Good luck!

Maggie

[OTRA15]

Unhook from shore power and the generator, then wait an hour to report the battery voltage. Your 13.6 reading is irrelevant as the gen is running. Ditto to glcmranger.

You stat may need a hard reboot. Check the AS owner's manual in general, as Maggie suggested, and then the Dometic manual that came with your AS briefcase. The hard reboot procedure is spelled out there. You have to perform a few simple keystrokes with the stat's control panel. Simple.

Your batteries may have been bad from the git-go, as some dealers do not maintain them well on the sales lot. An Interstate battery dealer (assuming this is what you have) will replace them if you can go by one on your travels.

Also, call the dealer as Maggie suggested.

BTW this is why we own RV's in general, to keep busy with quality control for the manufacturers! Quite a learning curve, but you will get there. Just can't hold on to expectations that this would be a "plug-and-play" process maybe? We have all been through this process.



Good luck!

Peter

[scroon]

Got two new batteries under warranty the furnace still won't light the batteries had dead cells

[OTRA15]

Originally Posted by scroon

Got two new batteries under warranty the furnace still won't light the batteries had dead cells

So do you hear the furnace ignitor sparking when it tries to light the propane? A trip to the dealer, or having a mobile RV service stop by, may be in order. What does your dealer say?

Bad sail switch or furnace circuit board sound like possibilities IMO.

Good luck!

Peter

[scroon]

I hope so

[scroon]

Rebooted the thermostat and the furnace still not kicking on

[Lily&Me]

You need to call the service department at your dealership, who can probably best help you troubleshoot, or schedule you an appointment to bring it in.

Let us know what you find.

Good luck,

Maggie

[AstroBruce]

Take the outside cover off the furnace. Check to see if the control board is wet.

Bruce

[ATownTX]

Hey all, just wondering if the line to the furnace has been completely purged of all air? Could that be it?

[Wingeezer]

Originally Posted by ATownTX

Hey all, just wondering if the line to the furnace has been completely purged of all air? Could that be it?

I would think that from the number of attempts to start the furnace the line should have purged by now - assuming of course that the gas valve is opening as it attempts to start.

[scroon]

I called the dealership and scheduled an appointment i didn't risk letting the local RV repair men working on my trailer talked to a couple of them and didn't feel confident in them