Free 7 Day Trial RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance 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 11-24-2021, 07:32 AM   #1
Twinlakes
New Member
 
Join Date: Nov 2021
Location: Twin Lakes
Posts: 1
M.O.C. #30148
Gas furnace

We have a 2021 3231CK and the gas furnace is not kicking on. We are full timing in Colorado at 9,000'. Need help quick! thanks


Update, after a series of off/on cycles, it finally kicked on.
 
Twinlakes is offline   Reply With Quote
Old 11-24-2021, 08:35 AM   #2
ChuckS
Montana Master
 
Join Date: Dec 2017
Location: Mountain Home
Posts: 553
M.O.C. #20949
Most likely if it had not been used in a while or the LP tanks were changed the furnace LP line still had air in it..

Normal sequence of events will always be.
1. Blower motor turns on and purges for 45 seconds
2. Sail switch moves to complete circuit via airflow from blower
3. Igniter fires and LP valve on furnace opens
4. Light off occurs.. furnace runs till set point reached
5. LP valve closes, furnace flame off, blower motor runs for 30 seconds to cool the furnace combustion section

IF light off doesn't occur the sequence of ignition retries 3 times and if not flame detected then it goes into lockout mode

To clear lockout mode turn furnace OFF and back ON.. sequence above will start again

Another weak area is the (Black ATC) style looking fuse often used on the Dometic/Atwood furnace.. This is not a standard fuse.. it is a resettable fuse that often doesn't function correctly and can give problems
ChuckS is offline   Reply With Quote
Old 11-24-2021, 09:35 AM   #3
jsb5717
Montana Master
 
jsb5717's Avatar
 
Join Date: Mar 2019
Location: Milwaukie, OR
Posts: 909
M.O.C. #23668
If the furnace is attempting to ignite, meaning you can hear the igniter clicking, then the sail switch is working correctly. If your furnace isn't trying to ignite then there are are a couple possible causes:

Sail Switch - this is the easiest thing to check first. It's easy for a bit of lint to get sucked into that switch, preventing it from closing and allowing ignition. After a few attempts it is possible for it to clear. But it's 2 screws and 2 wired connectors to remove and check it. Make sure it's clean. Since it currently sounds like an intermittent issue I would suspect the Sail Switch.

If the Sail Switch is clean then it could also be your control board
__________________

Jeff & Sandi (and Teddy - 7lb Schnorkie)
2018 Montana HC 305RL / Andersen Ultimate Hitch on B&W Ball
2012 RAM 3500 Big Horn Crew Cab 4x4 SRW / AMP Power Running Boards / Air Bags
jsb5717 is offline   Reply With Quote
Old 11-24-2021, 11:07 AM   #4
R.S.O'Donnell
Montana Fan
 
Join Date: Feb 2020
Location: NY and CA
Posts: 461
M.O.C. #25842
Quote:
Originally Posted by Twinlakes View Post
We have a 2021 3231CK and the gas furnace is not kicking on. We are full timing in Colorado at 9,000'. Need help quick! thanks


Update, after a series of off/on cycles, it finally kicked on.
Ours was doin the same. It was acting like the flame sensor/ignitor wasn't detecting a flame until it had gone through several tries. I attempted to remove the ignitor but too much had to be removed to get it out with the time I had so I put the screws back in. Inexplicably it worked flawlessly after that. It's been working perfectly ever since.

This is the best explanation I've found on how they work:

R.S.O'Donnell is offline   Reply With Quote
Old 11-24-2021, 12:01 PM   #5
jsb5717
Montana Master
 
jsb5717's Avatar
 
Join Date: Mar 2019
Location: Milwaukie, OR
Posts: 909
M.O.C. #23668
Quote:
Originally Posted by R.S.O'Donnell View Post
Ours was doin the same. It was acting like the flame sensor/ignitor wasn't detecting a flame until it had gone through several tries. I attempted to remove the ignitor but too much had to be removed to get it out with the time I had so I put the screws back in. Inexplicably it worked flawlessly after that. It's been working perfectly ever since.

This is the best explanation I've found on how they work:

Interesting, but is that an RV furnace? Looks residential to me. Unless there is a recent change the igniter would be the spark type that you can hear clicking as it attempts to light. That same scenario, though, was happening to us. ie.: actually igniting but turning right back off. For us it turned out to be the propane regulator, which wasn't supplying a flow adequate for the high demand of an RV furnace. New regulator solved the problem.

Question for the OP is whether the furnace is failing before or after the igniter attempts to fire. That will help to trouble shoot if the issue is pre or post ignition.
__________________

Jeff & Sandi (and Teddy - 7lb Schnorkie)
2018 Montana HC 305RL / Andersen Ultimate Hitch on B&W Ball
2012 RAM 3500 Big Horn Crew Cab 4x4 SRW / AMP Power Running Boards / Air Bags
jsb5717 is offline   Reply With Quote
Old 11-27-2021, 10:27 AM   #6
R.S.O'Donnell
Montana Fan
 
Join Date: Feb 2020
Location: NY and CA
Posts: 461
M.O.C. #25842
It is a residential but from what I understand the flame sensor functioning is similar. In my case it must have been some glitch with the flame sensor (which is integral with the spark ignitor).

Quote:
Dometic™ Atwood 35100 Hydroflame RV Furnace Igniter Electrode
The furnace electrode is both a conductor establishing an electrical spark at the Burner to ignite the air to gas mixture, and a sensor to signal the circuit board the flame is established.

Mine would light for a few second and the gas valve would abruptly cut off. After repeating this several times on it's own it would relight and stay lit.
R.S.O'Donnell is offline   Reply With Quote
Old 11-27-2021, 01:27 PM   #7
jsb5717
Montana Master
 
jsb5717's Avatar
 
Join Date: Mar 2019
Location: Milwaukie, OR
Posts: 909
M.O.C. #23668
Quote:
Originally Posted by R.S.O'Donnell View Post
Mine would light for a few second and the gas valve would abruptly cut off. After repeating this several times on it's own it would relight and stay lit.
Yeah, that's exactly what ours was doing. At first it would eventually stay lit after several failed attempts and resets. Ultimately it was still the regulator. The OEM regulators on these aren't great. A new Marshall Excelsior solved it for us.
__________________

Jeff & Sandi (and Teddy - 7lb Schnorkie)
2018 Montana HC 305RL / Andersen Ultimate Hitch on B&W Ball
2012 RAM 3500 Big Horn Crew Cab 4x4 SRW / AMP Power Running Boards / Air Bags
jsb5717 is offline   Reply With Quote
Old 12-01-2021, 03:35 PM   #8
ACKLM8
Established Member
 
Join Date: Jan 2020
Location: Springfield
Posts: 31
M.O.C. #25709
If someone has not already noted, the circuit board on the furnace has a flashing error code light. 1 flash every 3 seconds for example means "airflow not proven" (i.e. sail switch problem). Other codes for other issues. Check dometic furnace manual.
ACKLM8 is offline   Reply With Quote
Old 12-01-2021, 04:00 PM   #9
Bob and Jeannette
Montana Fan
 
Bob and Jeannette's Avatar
 
Join Date: Sep 2018
Location: Orlando
Posts: 330
M.O.C. #22589
Quote:
Originally Posted by jsb5717 View Post
If the furnace is attempting to ignite, meaning you can hear the igniter clicking, then the sail switch is working correctly. If your furnace isn't trying to ignite then there are are a couple possible causes:

Sail Switch - this is the easiest thing to check first. It's easy for a bit of lint to get sucked into that switch, preventing it from closing and allowing ignition. After a few attempts it is possible for it to clear. But it's 2 screws and 2 wired connectors to remove and check it. Make sure it's clean. Since it currently sounds like an intermittent issue I would suspect the Sail Switch.

If the Sail Switch is clean then it could also be your control board
At the rally a Dometic Tech told me that the previous generation of sail switch (last year included) had a design issue and was prone to fail. I had replaced mine last winter and Amazon sent me another old design. Works so far.
__________________
2020 Montana 3813ms legacy w/Paint
2017 Ram 3500 4X4 DRW Aisin Curt Q-25
Bob and Jeannette is offline   Reply With Quote
Reply

Tags
gas furnace

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

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 02:23 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2022, vBulletin Solutions, Inc.