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

Go Back   Montana Owners Club - Keystone Montana 5th Wheel Forum > MOC Technical Forums > Montana Problems, Problem Solving & Technical Help
Click Here to Login

Reply
 
Thread Tools Search this Thread Display Modes
 
Old 07-25-2021, 03:31 PM   #21
bcrvman
Montana Master
 
Join Date: Jun 2020
Location: Qualicum Beach
Posts: 665
M.O.C. #26399
Quote:
Originally Posted by Mopar_Mudder View Post
Their never is a blinking light because it never stops trying to light and their is no code to show. Their is no electronic part failing to create a code.

At this point I thing I am going to order a new gas valve, orifice and burner. Even though to burner look now. May get a new pressure regulator also even though my manometer shows no pressure problems.
When you find the cause of your problem it would be nice if you posted it so everyone can learn. I still bet it's the board as I had the same symptoms or the high limit.
 
__________________
2018 Keystone Montana 3811MS
2017 Ford F450 diesel dually
600AH Battle Born Lithium Batteries, 1,080 watts solar
3,000 watt hybrid inverter with 120A charger
bcrvman is offline   Reply With Quote
Old 07-25-2021, 03:48 PM   #22
Mopar_Mudder
Established Member
 
Join Date: Jun 2021
Location: Rice Lake
Posts: 37
M.O.C. #29014
Thier is no way it is the board or any switch. I have bypassed them all by supplying power direct to the valve.
Mopar_Mudder is offline   Reply With Quote
Old 07-25-2021, 03:59 PM   #23
Mopar_Mudder
Established Member
 
Join Date: Jun 2021
Location: Rice Lake
Posts: 37
M.O.C. #29014
Pulled the burner out and lit it manually outside the furnace. It does light and burn but seems like alot of flame to me, talking like 2' of the burner.
Attached Thumbnails
Click image for larger version

Name:	20210725_165540.jpg
Views:	37
Size:	114.3 KB
ID:	9785  
Mopar_Mudder is offline   Reply With Quote
Old 07-25-2021, 04:01 PM   #24
Bob and Jeannette
Montana Fan
 
Bob and Jeannette's Avatar
 
Join Date: Sep 2018
Location: Orlando
Posts: 338
M.O.C. #22589
Quote:
Originally Posted by Mopar_Mudder View Post
2017 3790rd and the furnace is an Atwood.



From my understanding if the sail switch is bad the exhaust fan doesn't run? My exhaust fan come on fine and blows hard. Unless it is suppose to be variable speed fan and it is blowing too hard for it to light?
Sail switch, cheap and easy repair, 15 minutes.
__________________
2020 Montana 3813ms legacy w/Paint
2017 Ram 3500 4X4 DRW Aisin Curt Q-25
Bob and Jeannette is offline   Reply With Quote
Old 07-25-2021, 04:28 PM   #25
Mopar_Mudder
Established Member
 
Join Date: Jun 2021
Location: Rice Lake
Posts: 37
M.O.C. #29014
I will ignore all sail switch comments as you are not listening or don't understand how the furnace works.

So I tried something. Turned the gas regulator down as far as I could, got down to 6-1/2" of water. Low and behold at that pressure the furnace lit and work fine. While it was running I turned the pressure back up to 11". Expected the flame to go out as it got more gas but it never did. The exhaust coming out was really hot, as in it would burn you pretty quick if you put you hand near it. I sut it down to see if it would start again and it did! Maybe because it was hot, I don't know. I will let it cool down and see what happens. All I know is it starts on lower pressure which kinda confirms my thoughts that the gas valve in the furnace also lowers the pressure, mine does not right now.
Mopar_Mudder is offline   Reply With Quote
Old 07-25-2021, 04:45 PM   #26
bcrvman
Montana Master
 
Join Date: Jun 2020
Location: Qualicum Beach
Posts: 665
M.O.C. #26399
Quote:
Originally Posted by Mopar_Mudder View Post
Pulled the burner out and lit it manually outside the furnace. It does light and burn but seems like alot of flame to me, talking like 2' of the burner.
I don't know what that should look like, but I am curious to find out. What would happen if the furnace was getting too much gas/pressure?

When you apply power direct to valve, it lights but goes out. Does gas still flow after the flame is extinguished? Reason I ask is there is an issue with oil in the gas lines (more prevalent west of the rockies) and if your line has a low point curve if that makes sense then enough oil at the right temperature can get blown uphill in the tube before falling back down and briefly blocking the flow of gas. In the picture of the flame, did it go out or keep going and could you smell gas after it went out?

Your troubleshooting technique is bang on, you have eliminated the sail switch and the high limit switch by applying 12V direct to the gas valve. Can you do a temporary gas line connection to eliminate the factory lines?
__________________
2018 Keystone Montana 3811MS
2017 Ford F450 diesel dually
600AH Battle Born Lithium Batteries, 1,080 watts solar
3,000 watt hybrid inverter with 120A charger
bcrvman is offline   Reply With Quote
Old 07-25-2021, 04:50 PM   #27
bcrvman
Montana Master
 
Join Date: Jun 2020
Location: Qualicum Beach
Posts: 665
M.O.C. #26399
Quote:
Originally Posted by Mopar_Mudder View Post
I will ignore all sail switch comments as you are not listening or don't understand how the furnace works.

So I tried something. Turned the gas regulator down as far as I could, got down to 6-1/2" of water. Low and behold at that pressure the furnace lit and work fine. While it was running I turned the pressure back up to 11". Expected the flame to go out as it got more gas but it never did. The exhaust coming out was really hot, as in it would burn you pretty quick if you put you hand near it. I sut it down to see if it would start again and it did! Maybe because it was hot, I don't know. I will let it cool down and see what happens. All I know is it starts on lower pressure which kinda confirms my thoughts that the gas valve in the furnace also lowers the pressure, mine does not right now.
That is different. How would a 12VDC valve control pressure though, it's a simple on/off as far as I can tell. Here is what I found.

Propane Gas Pressure
All propane appliances are designed to operate from a propane (LPG) supply that is at a standard pressure of 11 water column inches of pressure (about 3 psi). This is measured with a tool called a manometer. The LP tank pressure is much higher than 11” WC, so the pressure in the system is controlled by an LP regulator at or near the main supply tank. Either high or low pressure can cause the burner to fail to light or work improperly. Oily residue in the tank can clog the regulator, causing it to deliver gas at an incorrect pressure or sporadically. And of course an empty tank has little or no pressure. An LP regulator is not expensive, so if you suspect a problem with the gas supply, replacing the regulator is usually more cost effective than hiring a professional to test it. LP regulators are standard parts, available at any LP gas dealer and many hardware and home stores. You do not need an RV specific part, but do not use a regulator intended for natural gas.
__________________
2018 Keystone Montana 3811MS
2017 Ford F450 diesel dually
600AH Battle Born Lithium Batteries, 1,080 watts solar
3,000 watt hybrid inverter with 120A charger
bcrvman is offline   Reply With Quote
Old 07-25-2021, 05:02 PM   #28
Mopar_Mudder
Established Member
 
Join Date: Jun 2021
Location: Rice Lake
Posts: 37
M.O.C. #29014
I did pull a plug on a low point in the LP line and no oil at all.

When I apply a direct 12v it would light an then go out when the burner was inside the furnace. Outside the furnace it would keep burning just fine.

At this point I ordered a new shut off valve because I don't trust it. I don't know if it does anything to the pressure but it does have a diaphragm for some reason.

Also FYI I found if you are testing the furnace with the cover off you still need to put the exhaust extention on. Other wise the intake fan sucks up the exhaust air and not enough oxygen.
Mopar_Mudder is offline   Reply With Quote
Old 07-25-2021, 05:25 PM   #29
bcrvman
Montana Master
 
Join Date: Jun 2020
Location: Qualicum Beach
Posts: 665
M.O.C. #26399
Quote:
Originally Posted by Mopar_Mudder View Post
I did pull a plug on a low point in the LP line and no oil at all.

When I apply a direct 12v it would light an then go out when the burner was inside the furnace. Outside the furnace it would keep burning just fine.

At this point I ordered a new shut off valve because I don't trust it. I don't know if it does anything to the pressure but it does have a diaphragm for some reason.

Also FYI I found if you are testing the furnace with the cover off you still need to put the exhaust extention on. Other wise the intake fan sucks up the exhaust air and not enough oxygen.
I found several references in docs that pressure was to be at least 11" WC. That is strange given you had it working at much lower. Something is weird for sure.
__________________
2018 Keystone Montana 3811MS
2017 Ford F450 diesel dually
600AH Battle Born Lithium Batteries, 1,080 watts solar
3,000 watt hybrid inverter with 120A charger
bcrvman is offline   Reply With Quote
Old 07-25-2021, 06:46 PM   #30
Ozarkwoods
Established Member
 
Join Date: May 2020
Location: Rapid City
Posts: 46
M.O.C. #26357
I had the exact issue it progressed from occasionally firing up running for 15 to 20 seconds and going out then lighting and running fine for the rest of the day to recently firing up going out after seconds. I pulled everything out and checked the burner, solenoids, heat sensor. Put everything back same issue. I had an extra board so I put that in. Took care of the problem.
__________________
2020 3813MS
2019 Chevy 3500 CC DRW, Duramax
Ozarkwoods is offline   Reply With Quote
Old 07-26-2021, 06:29 AM   #31
L0veless
Montana Fan
 
Join Date: Oct 2016
Location: Saint George
Posts: 188
M.O.C. #19132
Send a message via AIM to L0veless
did you by pass the thermal switch?
I had the same issue with everyone saying "sail switch" just as you my furnace went on to the next step of igniting for 5-20 seconds then shutting down. board was not getting signal of heat and shut the gas off. good luck and please post what the issue was once it fixed.
__________________
2016 Ram 3500 DRW pulling 2016 Montana 3720RL
living in UT. wandering around with my best friend (38) years married and the royals (2 Saint Bernard's)
L0veless is offline   Reply With Quote
Old 07-26-2021, 06:53 AM   #32
Jeff & Deb M.
New Member
 
Jeff & Deb M.'s Avatar
 
Join Date: Jul 2017
Location: Hampton
Posts: 9
M.O.C. #20211
Quote:
Originally Posted by Mopar_Mudder View Post
Well I have been trouble shooting with no success. I have an AFMD35131 that is giving me issues. RV is new to me and the furnace didn't seem to give off alot of heat and now it doesn't give any at all. Exhaust fan kicks on as expected and then furnace will light for a second or two and go out. This process goes on forever, light and go out. It almost seems like a lack of gas or air so that the fire can't keep going. It does have a new burner and igniter.

I know everyone's first thought will be the gas valve is being shut off because of no signal from the flame sensor, but that is not what is happening. The gas valve does shut off but it is a few seconds after the flame goes out. I also verified this by jumping constant power to the valve so that it stayed open, flame still goes out.

I have blown compressed air through the flue and found nothing blocking it. Air flow is good coming out when the fan is on. In have cleaned the orifice in the valve, it was not dirty. I checked gas pressure tonight at the fitting that hooks to the furnace and got 10-3/4", I think it calls for 11". Water heater, fridge, stove all work fine.

I can't see where it can be anything electrical when the valve is open and gas is coming out it doesn't burn. Only thing I see is where the metal shroud of the gas valve hits the plastic shroud of the blower the plastic had melted a little. So their is not a perfect seal for the fan blowing into the burner, but the way it is designed I don't think their ever was.
I've heard of this happening before and the problem was the regulator. Replaced the regulator and the problem was fixed. Good luck!
__________________

Jeff & Deb M. plus Georgie & Milo
2017 Montana 3920FB - Legacy Edition
2019 Ford F-350 DRW 6.7 Diesel CC LWB
Jeff & Deb M. is offline   Reply With Quote
Old 07-26-2021, 06:57 AM   #33
Greg n Tracy
Established Member
 
Join Date: May 2019
Location: council bluffs
Posts: 40
M.O.C. #24154
I am curious as to what elevation you are at when experiencing the problems. We have the very same issue when at elevations higher than 5K'. Atwood says furnace "is not designed to work above 4K' ", or 4500, depending on who answers the phone/email. We had replaced everything except the board (regulator, burner, hi-low switch, sail switch) to no avail. We have now replaced the entire furnace, and will test it over the next few months as we head west into elevations again. Crossing our fingers that it will work.
Greg n Tracy is offline   Reply With Quote
Old 07-26-2021, 07:29 AM   #34
MOODY
Seasoned Camper
 
MOODY's Avatar
 
Join Date: Sep 2019
Location: Rattan
Posts: 67
M.O.C. #24936
On mine I noticed a drop in voltage to 3 volts from the circuit board to the high limit switch - but only occurred with temps below 40 degrees. By applying heat (heat gun) to circuit board the voltage would come back to 12 volts due to bad circuit board solder joint. I had 12 volts from circuit board to the sail switch at all times.

Furnace would light but go out after 3-4 seconds, fan continues to run, furnace relights, continuous process
__________________

Kevin & Pat Moody
2020 Montana 3701LK, Legacy Package, Satellite, Solar, Generator, 2019 Ford F350 Dually, BD5F Trailer Saver, 12' Trailer with Kayak Rack, Polaris General XP 4 1000
MOODY is offline   Reply With Quote
Old 07-26-2021, 07:30 AM   #35
jdarwin
Montana Fan
 
jdarwin's Avatar
 
Join Date: May 2018
Location: Bedford
Posts: 307
M.O.C. #21728
We have the same model furnace. Had the same problem. It’s a bad sail switch. I was told there was a bad batch of switches. If you pull it and test it, it will test good but doesn’t work. We replaced ours and no more problem.
__________________
Member #21728
2019 3931FB
2017 F350 6.7 Powerstroke SRW
B&W Companion Slider 20K
jdarwin is offline   Reply With Quote
Old 07-26-2021, 07:33 AM   #36
Daryles
Montana Master
 
Daryles's Avatar
 
Join Date: May 2019
Location: Alton
Posts: 2,654
M.O.C. #24086
You mentioned above
"Exhaust fan blows hard"
And it does burn when you removed it and lit it OUTSIDE the furnace.
Any chance the exhaust fan is blowing too hard and blowing it out???
__________________
Daryl and Marianne,
2019 3130re 20th Anniversary Edition
2016 F350 Lariat
Daryles is offline   Reply With Quote
Old 07-29-2021, 09:06 AM   #37
MOODY
Seasoned Camper
 
MOODY's Avatar
 
Join Date: Sep 2019
Location: Rattan
Posts: 67
M.O.C. #24936
Just checked my furnace agin last night - outside temp 68. Furnance blower starts, sail switch checks ok, furnace lights for approx 5 seconds & then goes out, blower continues, furnance relights after approx 10 seconds but goes out again after 5 seconds. This repeats itself.
Scheduled to have Keystone check during the Nat’l Fall Rally
__________________

Kevin & Pat Moody
2020 Montana 3701LK, Legacy Package, Satellite, Solar, Generator, 2019 Ford F350 Dually, BD5F Trailer Saver, 12' Trailer with Kayak Rack, Polaris General XP 4 1000
MOODY is offline   Reply With Quote
Old 07-29-2021, 10:08 AM   #38
Bob and Jeannette
Montana Fan
 
Bob and Jeannette's Avatar
 
Join Date: Sep 2018
Location: Orlando
Posts: 338
M.O.C. #22589
Quote:
Originally Posted by jdarwin View Post
We have the same model furnace. Had the same problem. It’s a bad sail switch. I was told there was a bad batch of switches. If you pull it and test it, it will test good but doesn’t work. We replaced ours and no more problem.
Same here!
__________________
2020 Montana 3813ms legacy w/Paint
2017 Ram 3500 4X4 DRW Aisin Curt Q-25
Bob and Jeannette is offline   Reply With Quote
Old 09-08-2022, 06:39 AM   #39
rames14
Montana Master
 
rames14's Avatar
 
Join Date: Aug 2004
Location: Livermore
Posts: 5,135
M.O.C. #1920
Mopar, did you determine a final fix to this. It’s been a year, so curious if adjusting the pressure was the final fix.
__________________
Ron and Terrie Ames - MOC #1920/KF0NTA
2021Montana 3230CK Super Solar Legacy Package
2021 Ram 3500 Laramie Longhorn, BIM Charging
4x4, SRW, LB, Crew Cab, Pullrite 3900 Hitch
rames14 is offline   Reply With Quote
Old 09-08-2022, 07:00 AM   #40
MOODY
Seasoned Camper
 
MOODY's Avatar
 
Join Date: Sep 2019
Location: Rattan
Posts: 67
M.O.C. #24936
Finally got mine fixed 60 days ago. Working great now at 5,725 elevation. Replaced ignitor switch twice, changed circuit boards, regulator - all to no avail. Read about a service bulletin that the original installers carried the furnaces by the gas lines as a handle. Correction was to push the gas line slightly at the furnace. Also read about the possibility of oil contamination in the gas lines.
Can't tell you which one fixed the problem but when relit it has worked for over 60 days now without a problem and I have had this problem for over a year. It used to be temperature related and eventually I could never get the furnace to stay lit - would always go out after 3-5 seconds and then relight again after 5-10 seconds. Makes me feel it wasn't the slightly bent gas line.
Took the gas line loose at the regulator and at the furnace and blew compressed air at 120 psi through the line. Didn't really notice anything come out the line but if you search the internet you will read lots of comments on oil contamination.
Once everything was working I installed a drop leg in the propane line just after the regulator to prevent oil/dirt contamination again if that was the problem. All homes have a drop leg for the same reason.
__________________

Kevin & Pat Moody
2020 Montana 3701LK, Legacy Package, Satellite, Solar, Generator, 2019 Ford F350 Dually, BD5F Trailer Saver, 12' Trailer with Kayak Rack, Polaris General XP 4 1000
MOODY is offline   Reply With Quote
Reply

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
Forum Jump

» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by Montana RV, Keystone RV Company or any of its affiliates. This is an independent, unofficial site.


All times are GMT -6. The time now is 01:18 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.