Furnace not igniting on 3011DS

Sherol · 03-23-2019, 08:47 PM

We own a 2018 3011Ds and the furnace has worked fine until we unwinterized and headed south a few days ago. Of course, the first thing I checked were the fuses under the bed and by the door. Everything is OK but I replaced the fuse under the bed to be sure. Took the doors off the heater inside and out and can hear it trying to ignite but it won't catch. The blower comes on and is blowing cold air. It doesn't appear to have wasp nests that I can see anyway. Blew it out with canned air and cleaned everything off. Propane is working fine for fridge and stove. Either the furnace is not getting propane or it is just not igniting. Could there be a fuse somewhere I am missing? Any ideas why it won't ignite? Hate to have to pay someone to tell me it was just a fuse somewhere else.

**Mr. Dan** · 03-23-2019, 09:11 PM

Quote:

Originally Posted by Sherol

We own a 2018 3011Ds and the furnace has worked fine until we unwinterized and headed south a few days ago. Of course, the first thing I checked were the fuses under the bed and by the door. Everything is OK but I replaced the fuse under the bed to be sure. Took the doors off the heater inside and out and can hear it trying to ignite but it won't catch. The blower comes on and is blowing cold air. It doesn't appear to have wasp nests that I can see anyway. Blew it out with canned air and cleaned everything off. Propane is working fine for fridge and stove. Either the furnace is not getting propane or it is just not igniting. Could there be a fuse somewhere I am missing? Any ideas why it won't ignite? Hate to have to pay someone to tell me it was just a fuse somewhere else.

I had the same symptoms last week. I was out of propane. Swapped tanks and all was well.

TheWolfPaq82 · 03-23-2019, 09:17 PM

Quote:

Originally Posted by Mr. Dan

I had the same symptoms last week. I was out of propane. Swapped tanks and all was well.

But his stove and Frig run fine on the propane side.

**Mr. Dan** · 03-23-2019, 09:18 PM

Quote:

Originally Posted by TheWolfPaq82

But his stove and Frig run fine on the propane side.

Yep....
Missed that.

TheWolfPaq82 · 03-23-2019, 09:26 PM

Do you hear the spark igniter clicking when it tries to ignite ?

What do think Dan...possible sail switch failure ?

**Mr. Dan** · 03-23-2019, 09:38 PM

Quote:

Originally Posted by TheWolfPaq82

Do you hear the spark igniter clicking when it tries to ignite ?

What do think Dan...possible sail switch failure ?

I wouldn’t think so since he says he “can hear it trying to ignite but it won't catch.” I’m not sure what he’d be hearing if the sail switch is bad.

A32Deuce · 03-23-2019, 09:48 PM

The stove and reefer don't use the volume of propane that the heater does. When my tank won't run the heater I can still run the stove for a couple minutes.

nomad297 · 03-24-2019, 08:10 AM

It sounds to me like you need to reset the regulator flow limiting device. You probably turned on your propane tank/s too quickly which can cause the regulator flow limiting device to activate which wil reduce the flow of propane from the regulator after the tank/s. In most cases, when this happens, you will get enough flow of propane for your refrigerator and your stove, but your stove burners will probably be a little smaller than usual, but you may not recognize this. You definitely won’t have enough flow of propane for your furnace, so you will hear the igniter clicking and you will be able to smell a slight odor of propane coming from the exhaust of the furnace on the outside of the camper.

Reset the flow limiting device by turning off the propane tank/s and disconnecting the propane lines from the tanks. Wait a few seconds, then reconnect the propane lines to the tank/s and turn on the tanks very slowly. Everything should be back to normal and you should now have sufficient flow of propane for the furnace to light.

I hope this is the problem and gets you warm.

Bruce

Tombsy · 03-24-2019, 11:06 AM

I’ve had this happen twice, (this is a built in tank on a mh). The low flow safety is built in the regulator you can tell if you light more than one stove burner and the second one will be only barely be on. The first time I changed the regulator but the second time I was able to thaw it with hot water.

Larry-NC · 03-24-2019, 06:39 PM

Quote:

Originally Posted by Mr. Dan

I wouldn’t think so since he says he “can hear it trying to ignite but it won't catch.” I’m not sure what he’d be hearing if the sail switch is bad.

Correct! It won't try to ignite if the blowers aren't up to speed causing the sail switch to remain open. It won't open the gas valve and it won't fire the spark.

(Everyone calls out the sail switch because it's the only part they understand.)

There are several possibilities, all named in the Suburban manual in the site library. Just follow the troubleshooting flow chart in this manual.

Interestingly, the first thing they tell you to check--and the most likely cause in trailers more than a few years old--isn't even in the furnace. It's the propane regulator, out in the weather between the two tanks. The water heater and range will operate across a wide range of pressures (the range has a secondary regulator so it won't even appear different), but the Suburban furnace is finicky.

Larry

Sherol · 03-24-2019, 07:40 PM

Hi, thank you for the replies. First of all, I'm a "she", lol. Also, we have a mh not a trailer and the propane tank is built in so I can turn it off but I can't disconnect the hoses. I am getting high flames on the stove and the fridge runs fine as I said. I will follow the steps that Suburban suggests and if it still won't work will have to pay for a repair. Thank you again for your suggestions.

Larry-NC · 03-24-2019, 08:06 PM

Quote:

Originally Posted by Sherol

Hi, thank you for the replies. First of all, I'm a "she", lol. Also, we have a mh not a trailer and the propane tank is built in so I can turn it off but I can't disconnect the hoses. I am getting high flames on the stove and the fridge runs fine as I said. I will follow the steps that Suburban suggests and if it still won't work will have to pay for a repair. Thank you again for your suggestions.

Sherol, the startup sequence for the Suburban furnace is something like this. (I can't remember the exact time periods).

Run the blowers for a minute or so to clear uncombusted fuel from the firebox so it doesn't go boom when it ignites. The firebox blower and the room circulation blower are on the same motor, so cold air will blow.
Activate the gas valve so gas flows and try to ignite the gas. You will hear a repeated clicking or sparking noise for maybe 10 seconds, less if it ignites.
If it fails to ignite, it will again purge the fire box for maybe another minute and repeat the ignition attempt. If it fails again (after the third attempt), it will give up and not make further attempts until you turn the thermostat from Heat to Off and back to Heat.

So here are a couple of questions for you:

This is all for the very common SF-series Suburban furnaces. Do you have a Suburban furnace or maybe an Atwood or something?
What did you mean when you said you had covers off inside and outside? There's nothing outside but a plate with two 3" holes on the furnace--one hole for Atwood. Weren't looking at the water heater, were you? (no offense)
Can you hear the gas valve open? Might sound like a clunk at the furnace.
Can you hear the sparking?
Can you hear the three tries?
Once you have the grille off at the inside, you should see the front of the furnace box. It's the plenum/heat exchanger. Along the top, front edge is a sensor called the high-limit switch. It's a cylindrical thing, a couple of inches long, with a slide-on connector at each end. It shuts off the gas but leaves the blowers on if the furnace gets too hot. With the furnace off, unplug a connector at either end and then measure resistance across the switch. It should be zero ohms (conducting). If it's open (high resistance) when it's cool, it needs to be replaced. If I remember right, there's a different part number for each size furnace. Check the manuals in the Library. (Alternatively, while attempting to run the furnace you could jumper across the high-limit switch FOR A TEST. Do not leave the jumper in place. It's not safe.) What were the results?
Try this test and report the results. The front cover of the plenum comes off with just two screws or so. Remove the cover and attempt to run the furnace. It is perfectly safe to do this. Does it light and produce heat?

Larry

TimVWulp · 03-24-2019, 09:58 PM

Quote:

Originally Posted by Sherol

Hi, thank you for the replies. First of all, I'm a "she", lol. Also, we have a mh not a trailer and the propane tank is built in so I can turn it off but I can't disconnect the hoses. I am getting high flames on the stove and the fridge runs fine as I said. I will follow the steps that Suburban suggests and if it still won't work will have to pay for a repair. Thank you again for your suggestions.

Hi Sherol with 3 of the stove burners on high start the furnace if the stove goes out or almost out the propane system con not provide the propane necessary to operate the system and will cause the furnace not to start. If the stove burners remain on and unchanged the propane system is operating properly and the furnace system is at fault.

Below is a link from the library at the top of this page in the light green bar. The link is a Suburban furnace manual that has a trouble shooting section at about page 26 that is very helpful to find the problem.

http://www.forestriverforums.com/for...?do=file&id=67

Hope this helps Tim

Sherol · 04-07-2019, 02:45 PM

We finally took it to a repair shop. They have ordered parts and we are waiting in a nearby RV park for them to come in. They told me the parts they were replacing but it was over my head. Just glad I purchased the extended warranty when we bought the motor home from Suburban and they are covering all expenses for the repairs.

You may also like: