Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > RV SYSTEMS AND TECHNOLOGIES FORUMS > RV Systems & Appliances
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 01-16-2022, 05:45 PM   #1
Member
 
Join Date: May 2019
Posts: 55
Dometic Furnace Stopped Working

Hoping there is an easy fix!
My Dometic DFMD35 was working fine for several nights then we had warmer weather for 3 nights and it didnít need to come on. I then had the propane tank filled. The next night it failed to come on. I got the flame signal on my interior control panel, but the blower did not turn on. My first thought was the propane fill may have caused this, but I cannot find anything amiss. I retried the start procedure many times to clear any potential air in the line. My propane water heater works fine, the furnace fuse is good, the furnace off/reset switch behind the furnace outside panel does not fix it.
SoÖI am beginning to think the failure after the propane fill was merely coincidental.
Troubleshooting further, I see a failure light sequence on the internal control board of a light flash every 3 seconds indicating an air flow problem. I am thinking the most probable failure is the sail switch. Iíll be in a spot where I can start to dismantle it in 2 days. We are in a spot now with power and getting by with a small electric heater until I get this fixed.
I thought I would reach out to the forum first to see if I am missing something obvious before starting the disassembly. Any thoughts?
__________________
Thor Miramar 34.2 2019
2020 Jeep Cherokee V6 4WD
Flyitall is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 01-16-2022, 08:12 PM   #2
Senior Member
 
Old-Biscuit's Avatar
 
Join Date: Nov 2015
Posts: 21,014
Sail Switch Stuck CLOSED will not allow furnace to run...circuit board checks and if it is not open the circuit board will not send DC to Fan Motor

Only One Blue wire in connector on circuit board (2nd one) should have 12VDC Voltage....until Fan runs then when Sail Switch closes the other Blue wire in that connector (top one) will have 12VDC Voltage

See wiring diagram pg 8 (AFM manual---same as DFM)
*AFM---Atwood Furnace Medium/DFM---Dometic Furnace Medium
https://manuals.heartlandowners.org/...wood%20AFM.PDF
__________________
Is it time for YOUR Medication or Mine?
Dodge 3500 w/Tractor Motor & NUWA 5vr
US NAVY---USS Decatur DDG-31
Old-Biscuit is online now   Reply With Quote
Old 01-18-2022, 07:08 PM   #3
Member
 
Join Date: May 2019
Posts: 55
Both the sail switch and the over temp sensor are working properly. I did find the voltage to the board is only 10 volts and should be 14.4 from my house batteries. I am currently trying to run this down but canít follow the orange lead thru the cable bundles and walls. Will try tomorrow from the other end.
__________________
Thor Miramar 34.2 2019
2020 Jeep Cherokee V6 4WD
Flyitall is offline   Reply With Quote
Old 01-18-2022, 08:27 PM   #4
Senior Member
 
Old-Biscuit's Avatar
 
Join Date: Nov 2015
Posts: 21,014
Low DC Voltage.......

DC to furnace should be from a FUSED source

Good luck IDng the wiring!
__________________
Is it time for YOUR Medication or Mine?
Dodge 3500 w/Tractor Motor & NUWA 5vr
US NAVY---USS Decatur DDG-31
Old-Biscuit is online now   Reply With Quote
Old 01-19-2022, 04:42 AM   #5
Senior Member
 
Join Date: Dec 2019
Location: NC
Posts: 887
Would running a good 12 volt lead from a known good battery to the circuit board be worth trying?
__________________
2005 Cummins 2WD 3500 LB CC dually 2014 Blue Ridge 3025RL
Toby Dog is offline   Reply With Quote
Old 01-19-2022, 07:55 AM   #6
Member
 
Join Date: May 2019
Posts: 55
Good idea! I’ll try that if I can’t figure out what’s happening with the existing wire.
__________________
Thor Miramar 34.2 2019
2020 Jeep Cherokee V6 4WD
Flyitall is offline   Reply With Quote
Old 01-19-2022, 08:37 PM   #7
Senior Member
 
Old-Biscuit's Avatar
 
Join Date: Nov 2015
Posts: 21,014
Don't forget about having a good ground!
__________________
Is it time for YOUR Medication or Mine?
Dodge 3500 w/Tractor Motor & NUWA 5vr
US NAVY---USS Decatur DDG-31
Old-Biscuit is online now   Reply With Quote
Old 01-21-2022, 02:50 PM   #8
Member
 
Join Date: May 2019
Posts: 55
Problem Solved!

I found my issue!
First, my fuse box labels were not correct which led me astray.
Second, the actual fuse in the distribution box was loose and not always making contact. There is a long line of automotive type blade fuses stacked closely together. When I tracked down the correct fuse, and detected looseness, I pulled it and examined it and could see the blade on one side was gouged by the mating connector and spread the metal on the connector. I think when the fuses were installed at the manufacturer, they forced two fuses in that spot and then removed one. This left the metal spread out so that the single fuse never made good contact. It did work fine for the few times I used it, but ultimately failed open. I just squeezed the metal back down and the fuse is snug.
__________________
Thor Miramar 34.2 2019
2020 Jeep Cherokee V6 4WD
Flyitall is offline   Reply With Quote
Old 01-21-2022, 08:40 PM   #9
Senior Member
 
Old-Biscuit's Avatar
 
Join Date: Nov 2015
Posts: 21,014
That's for update and resolution!

Much appreciated...

Cheap/free fixes are GREAT!
__________________
Is it time for YOUR Medication or Mine?
Dodge 3500 w/Tractor Motor & NUWA 5vr
US NAVY---USS Decatur DDG-31
Old-Biscuit is online now   Reply With Quote
Reply

Tags
ace, dometic, furnace



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
My TT furnace stopped working... Tcecil Travel Trailer Discussion 8 11-17-2013 06:37 PM
Furnace stopped working mrschwarz Winnebago Industries Owner's Forum 13 01-23-2008 04:10 AM
Furnace stopped working! RobG RV Systems & Appliances 5 09-25-2007 12:05 PM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 08:54 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2022, vBulletin Solutions, Inc.