Recurring Furnace Issue

jalad12 · 03-10-2021, 10:15 AM

Hi everyone! I’ll try to make this short and direct. I have a 2019 Cougar 27Res. About 6 months ago my furnace turned on but did not blow hot air. It turned off about a minute later. I had propane so after reading this forum I removed the furnace to check the sail switch. Using a multimeter the sail switch tested good. I reinstalled the sail switch and the furnace and it worked! We took several trips with no furnace issues. On the road now and the furnace did the same thing. Turn on, no heat, turn off. I pulled the furnace, tested the sail switch and it tested good. Replaced the furnace and it worked fine for a week. Now it’s doing the same thing again! Both propane tanks are full! Could the sail switch be intermittent?

jsb5717 · 03-10-2021, 11:51 AM

First thing I'd try is to check all of the wire connections. Sometimes just removing them and reinstalling them can solve it. Jiggle them a bit as you do that to make sure they are making good contact

Is the furnace igniting then turning off? Is it attempting to ignite and failing? If there's no attempt to ignite then it could be something intermittent with the sail switch, or main board itself. If it is attempting to ignite and failing then it could be in incorrect gap of the igniter to the burner mesh. Is it tight? Refer to your manual for the correct distance for the gap. Also just check to see if a critter has made a nest somewhere in the propane tube...maybe it's just not getting adequate flow.

Anyway, just some initial thoughts. There are some good YouTube videos that talk about troubleshooting both pre- and post-ignition failures. Good luck.

jalad12 · 03-10-2021, 01:38 PM

The furnace blows air but it does not attempt to ignite.

ChuckS · 03-10-2021, 03:22 PM

Since you’ve pulled and tinkered with sail switch twice and it works a bit then doesn’t the sail switch is defective... either crap is inside of the switch preventing contacts from mating all the time or the paddle arm is hanging up on something when blower motor runs

You will not hear the igniter firing if sail switch doesn’t close to complete the circuit OR high limit switch is open

These are the only two things outside of dirty connections on igniter control board or issues with board itself

I’d start with least expensive item and replace sail switch

**JRTJH** · 03-10-2021, 04:12 PM

If I understand the Suburban sail switch recall, it's because there is a "problem" with the sail switch "sail arm" hanging up on a burr/indentation on the body of the switch. Occasionally, the arm on the sail will hang up on that bump and not fully close the switch contacts... That puts the furnace in "lockout mode" and the ignition sequence stops.

From your description of what you've done, I'd suspect that your sail switch is one of the components that "caused the recall in the first place"... You say that by pulling the furnace, removing the switch, then on reinstallation, everything works, I'd believe that you are "perfectly describing" the reason for the recall.
It'll work for several times, then eventually, that arm will hang up again and the furnace stops working.

Get a newly designed sail switch (that doesn't have that bump in the way of the sail switch arm) and I'd almost bet your furnace issues will completley go away.....

jalad12 · 03-10-2021, 05:33 PM

Thank you all for your informative, and consistent, responses. I’ve ordered a new sail switch. When it arrives I’ll install it and and report back on how things work.

I’m not familiar with the recall but as an afterthought, is it possible to file down the bump that the metal piece gets stuck on? Again, I’m not familiar with the recall or where the bump is. But if it’s accessible, I’m game for anything!

**JRTJH** · 03-10-2021, 06:28 PM

It won't hurt to try. I've heard (actually read on the forum) about a couple of people who used a file to enlarge the opening in the furnace body. One person said there was a lip on the cutout and their sail switch was hanging up on that lip. Another said the switch was "hanging up internally". I'd make a WAG that switch couldn't be improved, but the first one could.

Since you're familiar with removing the switch, take it off the furnace, see if there's any rough edges around the opening where it fits on the furnace body and then check the switch to see if you can "feel or see" any rough spots when moving the sail arm.

It may not be possible to fix it, but then again, it might get you a serviceable spare for the future..... Let us know what you find.

jasin1 · 03-10-2021, 06:50 PM

Quote:

Originally Posted by JRTJH

It won't hurt to try. I've heard (actually read on the forum) about a couple of people who used a file to enlarge the opening in the furnace body. One person said there was a lip on the cutout and their sail switch was hanging up on that lip. Another said the switch was "hanging up internally". I'd make a WAG that switch couldn't be improved, but the first one could.

Since you're familiar with removing the switch, take it off the furnace, see if there's any rough edges around the opening where it fits on the furnace body and then check the switch to see if you can "feel or see" any rough spots when moving the sail arm.

It may not be possible to fix it, but then again, it might get you a serviceable spare for the future..... Let us know what you find.

I don’t know why rv furnace manufacturers would stick with a sail switch... they could come up with a pressure switch that would be more reliable I would think.. most residential furnaces use pressure switches... years ago we used to use sail switches when adding electronic air cleaners but even they use a built in airflow switch now

jalad12 · 03-11-2021, 03:31 PM

I remove the sail switch, yet again.��. I felt inside the housing and could not find any rough spots or dimpling. It all felt smooth. I then turned the sail switch so that the sail arm could rest on the switch. Doing this, the switch closed about three out of every five attempts. I know it’s not very scientific but it was the only way to have a consistent test. I blew on the sail arm several times however I had no way of regulating how much airflow was actually hitting the sail arm at any given time. I’ve reinstalled the sail switch until the new switch arrives in the mail. I hope it lasts more than just one or two cycles. I’ll let you all know. Again, thanks for all your help!

jasin1 · 03-11-2021, 04:19 PM

Quote:

Originally Posted by ChuckS

Since you’ve pulled and tinkered with sail switch twice and it works a bit then doesn’t the sail switch is defective... either crap is inside of the switch preventing contacts from mating all the time or the paddle arm is hanging up on something when blower motor runs

You will not hear the igniter firing if sail switch doesn’t close to complete the circuit OR high limit switch is open

These are the only two things outside of dirty connections on igniter control board or issues with board itself

I’d start with least expensive item and replace sail switch

Quote:

Originally Posted by JRTJH

If I understand the Suburban sail switch recall, it's because there is a "problem" with the sail switch "sail arm" hanging up on a burr/indentation on the body of the switch. Occasionally, the arm on the sail will hang up on that bump and not fully close the switch contacts... That puts the furnace in "lockout mode" and the ignition sequence stops.

From your description of what you've done, I'd suspect that your sail switch is one of the components that "caused the recall in the first place"... You say that by pulling the furnace, removing the switch, then on reinstallation, everything works, I'd believe that you are "perfectly describing" the reason for the recall.
It'll work for several times, then eventually, that arm will hang up again and the furnace stops working.

Get a newly designed sail switch (that doesn't have that bump in the way of the sail switch arm) and I'd almost bet your furnace issues will completley go away.....

Has anyone one ever tried ( just for emergency until new part arrives) putting a small weight on the sail switch? Not for permanent use but if you were on a camping trip and needed heat with a intermittent switch. Like a small self tapping screw into the sail?

On the old Honeywell sail switches we used to put a screw or bolt in the sail if the return air wasn’t sufficient to pull the switch closed.. it allowed it to close with less pressure... as long as it still returns to the “open” setting when the fan shuts off it will not bypass any safety’s... and if it didn’t return to “open” the furnace should only operate the one cycle as it likely needs to prove both “open” and “closed”....I wonder if the sensitivity of the switches or the weight or length of the sail could be improved..maybe cheaper metals weigh less and require more airflow to engage... or possibly the spring is too strong from the made in China parts

ChuckS · 03-12-2021, 06:04 AM

First the issue with the sail switches is related to Dometic/Atwood.. not Suburban

Second the issue with the sail switch is more than likely due to CHEAP components used in the inside workings of the switch itself... as evidenced via the OPs continuity test

The contact surfaces are mating poorly and most likely have oxidation or something on the surface of the contacts and they will never work worth a hoot..

This issue started showing up about 18 months ago on many Atwood furnaces... brand new units right off the assy line wouldn't work or quit shortly after purchase....

Dometic/Atwood has failed to step up to the plate and find a vendor that can build a simple switch that works reliably... and they have failed to take care of the customer across all brands

jalad12 · 03-14-2021, 03:49 PM

Thanks for your input, ChuckS! My unit is a 2019 and to your point, the problem reared it’s ugly head about one year after purchase. My new sail switch is in the mail. When I last removed the sail switch I bent the sail arm, twisted it and did what I could think of to free up the mechanism from any potential binding. It’s been about 5 days since then and I’ve had no furnace issues (fingers crossed!). I’ll hold on to the new sail switch when it arrives and install it if the current switch fails again.

jalad12 · 03-20-2021, 03:11 PM

My new sail switch arrived and it’s been almost two weeks since I’ve had any furnace issues using the (old) existing sail switch. Should I replace the old sail switch with the new one and hold onto the old one as a backup? My reasoning is such: If I do not immediately install the new switch I will not know if it works. If I wait until the old one craps out again (if it does) the new one may be out of warranty. Thoughts??

jasin1 · 03-20-2021, 03:22 PM

Quote:

Originally Posted by jalad12

My new sail switch arrived and it’s been almost two weeks since I’ve had any furnace issues using the (old) existing sail switch. Should I replace the old sail switch with the new one and hold onto the old one as a backup? My reasoning is such: If I do not immediately install the new switch I will not know if it works. If I wait until the old one craps out again (if it does) the new one may be out of warranty. Thoughts??

Well hmmmm if your concerned about the warranty then I would install it now and save the old one for an emergency... how much was it? If it’s under $50 I would probably forget the warranty and save it for when you eventually need it... pretty unlikely that the new one has anything wrong with it but you could test it with a meter if you really wanted to

jalad12 · 03-21-2021, 09:26 AM

Thanks, Jasin. The old one tested ok with a meter but it didn’t always make contact, or it got hung up during actual operation. I was a little rough with it the last time I had it out and it’s been working fine since (*insert chauvinistic comment here* ��). Yes, the warranty was my concern but for $26 I can hold the new switch in reserve to be used if/when the existing one fails again. Besides, I’m tired of removing the furnace!! ��

AnJ · 03-25-2021, 07:55 AM

Quote:

Originally Posted by jalad12

Thanks, Jasin. The old one tested ok with a meter but it didn’t always make contact, or it got hung up during actual operation. I was a little rough with it the last time I had it out and it’s been working fine since (*insert chauvinistic comment here* ��). Yes, the warranty was my concern but for $26 I can hold the new switch in reserve to be used if/when the existing one fails again. Besides, I’m tired of removing the furnace!! ��

My brother is having the EXACT same issue. Can you please tell me from where you ordered your replacement switch. Also, I am very interested to know how you bent the sail. It seems to me that his sail was very wobbly in its travel. I'm wondering if bending it doesn't assist the blower fans force on it compensating for the shaky travel of the sail.

colouiss651 · 03-25-2021, 08:37 AM

Quote:

Originally Posted by jalad12

Hi everyone! I’ll try to make this short and direct. I have a 2019 Cougar 27Res. About 6 months ago my furnace turned on but did not blow hot air. It turned off about a minute later. I had propane so after reading this forum I removed the furnace to check the sail switch. Using a multimeter the sail switch tested good. I reinstalled the sail switch and the furnace and it worked! We took several trips with no furnace issues. On the road now and the furnace did the same thing. Turn on, no heat, turn off. I pulled the furnace, tested the sail switch and it tested good. Replaced the furnace and it worked fine for a week. Now it’s doing the same thing again! Both propane tanks are full! Could the sail switch be intermittent?

I have a Keystone Outback that did the same thing. I know this will sound insane, but is the truth. I had a mobile technician out. Through a series of uninstalls and reinstalls, and conversations with the furnace manufacturer, we learned that the furnaces were being mis-handled by employees at the factory when building the camper. They were literally picking up the furnaces by the gas intake tubes when installing them (the tube running down the side looks like a perfect handle to pick them up). This actually slightly bent the intake so that it did not line up with the intake port as it should. By slightly bending (and I do mean very sligthly) the tube in the other direction back toward the body, the problem was solved. That was two years ago and we havent had a problem. The manufacturer agreed to pay my technicians fee.

jim1 · 03-25-2021, 08:50 AM

Hey sorry to hear about the sail switch issue. I had the same issues in our 2019 Cougar 315 RLS, but mine only quit working on our first trip and only at 3 or 4 am, nice. I removed it and cleaned construction debris off and it worked for 2 more days until a cold early morning, I again pulled it apart cleaned it and bent it a little bit and it's still working (knock on wood). I had a very frank and not nice discussion with my local dealer about lack of sleep and freezing our a$$#@ off and fixing it in the dark cold middle of the night. He graciously ordered us a new sail switch and wanted to install it for no charge. I agreed only if I could install it myself, since I really knew the furnace and sail switch after repeatedly work on it in the dark cold nights. Needless to say but I still have not needed to change the sail switch yet so I now have an emergency switch and the ability to replace it with my eyes closed. Seems like nothing ever goes wrong when your ready for it.

tbirdkeys · 03-25-2021, 10:57 AM

I had the exact same problem with my furnace in my Forrest River Sandpiper for several years. I replaced the sail switch 3 times and furnace would work for a while, then quit. I would pull it out, check the switch which would bench test as good, put it back in and it would work again for a while then quit. 😡. It was especially irritating to me because it was a royal pain in my a$$ to remove the furnace.

I finally ordered a replacement motherboard for about $90 bucks and it finally fixed the problem for good. I would definitely try that if your still having problems.

Ryan

jalad12 · 03-25-2021, 11:16 AM

Quote:

Originally Posted by AnJ

My brother is having the EXACT same issue. Can you please tell me from where you ordered your replacement switch. Also, I am very interested to know how you bent the sail. It seems to me that his sail was very wobbly in its travel. I'm wondering if bending it doesn't assist the blower fans force on it compensating for the shaky travel of the sail.

I ordered the sail switch online from Panther RV Products https://pantherrvproducts.com/

Dometic™ Atwood 33082 Furnace Sail Switch With Bracket Upgrade Kit
26.89 plus shipping. It cost me $30.47 out the door. The 33082 is my furnace model number. Your brother should verify the furnace make and model number before ordering.

I gently bent the sail so there was a bit more arch in it. But don't bend it too much because it may hit the blower blades if bent too much. I still have the old sail switch installed and it's working fine after several weeks. Good Luck!

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