2020 Momentum G21 - furnace not lighting

[49scott]

Hi all. I’m new to the GD family. I recently was on a camping trip and ran myself out of propane. When I refilled the bottle and purged the lines I’m still not getting heat. Fridge and stove run on propane, blower turns on, but no ignition.
Any thoughts?? I pulled the cover on the outside and held down the sail switch and still nothing. The front of the furnace is under the stove and no room to get to the thermostat. Very frustrated as this unit is only 6 months old.

[Country Campers]

How many times did you try to cycle the furnace? It may take 3 or 4 times , maybe more to get the air purged out of the line. I can not imagine that just running out of propane would cause any other mechanical issue.

Brian

[ThePowells]

49scott Welcome to the forum and the family! As Brian commented, it may be as simple as needing to be purged. Are you hearing any clicking or seeing the igniter spark? It also may be that you may have to cycle the thermostat off and then back on and attempt for it to light again.

The moderators have put together a great tool to help new members navigate our sandbox, https://gdrvowners.com/forum/main-fo...to-new-members I hope it may provide some help in getting the most out of the forum.

[howson]

Hi all. I’m new to the GD family. I recently was on a camping trip and ran myself out of propane. When I refilled the bottle and purged the lines I’m still not getting heat. Fridge and stove run on propane, blower turns on, but no ignition.
Any thoughts?? I pulled the cover on the outside and held down the sail switch and still nothing. The front of the furnace is under the stove and no room to get to the thermostat. Very frustrated as this unit is only 6 months old.

49Scott--noted that was your first post, so when able please check out the Welcome Letter to New Members at https://gdrvowners.com/forum/main-fo...to-new-members

First, though, the Furnace Troubleshooting thread in the HVAC > Reference Material channel may be helpful to troubleshoot the issue with the furnace. Unfortunately the problem may be the control panel--quite common.

Howard

[TucsonJim]

Since you have a new unit, we can't assume what type of furnace you have. Due to the supply chain being impacted by Covid, GDRV frequently has to substitute products in order to get them built. Do you happen to know the make and model of the furnace and thermostat supplied with your 21G?

Jim

[49scott]

Wow. Thank you all for your support. I’ve tried to combine all the responses below.
First, the unit is a Suburban SF-30Q. I’ve cycled it probably at least 8x. My version of cycling is turning the thermostat to 80* and to “heat”. I hear the blower kick on for @ 30 seconds and then nothing. I wait @ 30 seconds more and then turn thermostat to off....then try again. Is there another version of “cycling”? I’m hearing no clicking and where would I look for a spark?
Any other thoughts on troubleshooting? Continuity test at the sail switch or check DC voltage? I”m just not sure where/what as I’ve never worked on furnaces before.

[TucsonJim]

Do you have a multi-meter?

If so, I'd check continuity on the sail switch with it depressed and not depressed. It should show continuity when you move it.

If that checks out, then I'd check the limit switch for continuity. It should be reading zero ohms. If it's open circuit while the furnace is off, the limit switch has failed.

If both the sail switch and the limit switch check out okay, then your control board has probably failed. You can typically purchase a replacement from Amazon for $80-$100. I'd recommend going with a Dinosaur brand replacement model due to their great reputation.

The attached video is excellent on showing how to locate and trouble-shoot the sail switch and limit switch. In the video, the owner traced the problem to the limit switch.
https://www.youtube.com/watch?v=_NW8mk66ReA

Jim

[49scott]

Thanks Jim.
I do have a multi-meter. I’ll check the sail switch but unfortunately I cannot get to the limit switch. I’ve watched that video and is where I started before going on to this forum. In the video he has access through a vent. My furnace is under my oven and no access even when I remove the bottom drawer. I’ll try the continuity on the sail switch and see. Other than that I may have to take it in for a warranty repair.

[colan]

Running for 20 - 30 seconds before shutting off points to either the sail switch not closing or an open limit switch, repeating what Jim said.

Limit switches seldom fail. What I’ve seen more often than a failed limit switch is a lose connection at the switch. If you can get to the back of the furnace typically one screw holds the rear panel in place for access to the limit switch.

On Suburban furnaces more often than a failed sail switch the issue is a failed blower wheel. Fan is moving insufficient or no air to close the sail switch. Looking closely in the open end of the blower you can usually see pieces of plastic.

Dometic sails switches have had a reputation for being problematic. Suburban sail switches are rock solid. So far this heating season two failed blower wheels and zero Suburban sail switches. BTW - Dometic appears to have fixed their sail switch issue with a redesign a year or two ago.

[49scott]

Merry Christmas all!!
I’m looking to see if anyone knows where to find the installation instructions for this furnace. I think I’m going to try and remove it so I can check the limit switch or board.

Thanks

[howson]

Merry Christmas all!!
I’m looking to see if anyone knows where to find the installation instructions for this furnace. I think I’m going to try and remove it so I can check the limit switch or board.

Thanks

I know I'm not directly answering your question...but please consider having the work done under your warranty. Disconnecting the gas line, ducts and all the wiring is no small task and could easily induce other issues.

If getting the trailer to a dealer is an issue, try calling Grand Design Customer Service and explain the issue. They might authorize a mobile technician. Note there is usually a "service fee" that you'll be responsible to pay (above and beyond the labor for any repairs which GD will cover if pre-approved).

Also, if you choose to pursue this option, ensure the mobile technician is certified to work on Suburban equipment or if a part is needed they (Suburban) may not ship it.

If you're still determined to do this yourself and 1) there's no response to a source or 2) you can't find it via Google, post again and when I get home (I'm at work--yes, on Christmas Day--I'll dig in my files and see if I have anything).

Howard

[d2reid]

Lets see if this works....

Suburban_Service_Manual.pdf

Check to make sure yours is the same as mine....

[RV Tech Ret]

Thanks Jim.
I do have a multi-meter. I’ll check the sail switch but unfortunately I cannot get to the limit switch. I’ve watched that video and is where I started before going on to this forum. In the video he has access through a vent. My furnace is under my oven and no access even when I remove the bottom drawer. I’ll try the continuity on the sail switch and see. Other than that I may have to take it in for a warranty repair.

Before you pull it all apart a couple of things...first check for 12VDC between the red and yellow wire on the connector going to the board. This is where the voltage that is sent thru the sail and limit switch tells the board everything is okay. I believe this model had a time delay relay also so if you DO NOT have 12 V on the red wire (yellow is ground) then check the relay for power going out (normally white wire) to the limit/sail switch - these relays are notorious for sticking. I agree with others if you are under warranty I would not be pulling everything apart - it could void the warranty.....taking it into a dealer I know is a REAL pain so contact a mobile Tech BUT make sure they are Suburban authorized so they can so the warranty work for you so much less painful.......ask them what their mobile fee is because that is all you should have to pay if they are a dealer....

Mark

[49scott]

Thanks everyone. I’ve tried contacting several dealers and no one will see me for several months. Very frustrating. Any idea on where to find a “mobile tech”? I googled and nothing comes up. I’d prefer not to do this work myself for sure but waiting months is not good either. Below is the manual I found online. It is 2015 vs the 2007 d2reid sent.

[howson]

Thanks everyone. I’ve tried contacting several dealers and no one will see me for several months. Very frustrating. Any idea on where to find a “mobile tech”? I googled and nothing comes up. I’d prefer not to do this work myself for sure but waiting months is not good either. Below is the manual I found online. It is 2015 vs the 2007 d2reid sent.

If you're in a campground, ask the front desk. If not in a campground, call the ones close to you and ask for references.

colan -- is there a referral network for mobile technicians/businesses like yourself?