another furnace question

[raygreg]

2019 Montana 3120RL
Furnace is not firing sometimes.,(fan comes on but no ignition). Board is mounted vertically so water there.
Single blinking light for fault code.
I took out the sail switch it was clean, showed continuity, put it back together and furnace is now working.
The question is: Is the sail switch supposed to "click" when I activate it or is it a silent switch.
Mine is silent.
TIA
Ray

[rohrmann]

Whether the switch makes a click or not doesn't really matter, and it's probably dependent on what micro switch the manufacturer used. The switches used are not designed to carry any current, but just provide a signal to the circuit board telling it there is sufficient air flow to allow the burner to activate. If the switch had to click each time, that might provide enough resistance to keep it from closing each time, so clicking may not be desired. If it's working, you are good. You may have just had a slightly poor connection and removing it and reinstalling it cleaned the contacts enough to make it work.

[raygreg]

That's sort of what I figured. Hope it is still working this morning.

[Rebel]

I have a similar issue with our 3812MS Montana in that the furnace fan will begin a cycle , run for a few seconds then shut down, control board indicates single flash (air flow problem) -- this is the second Montana we have owned that has had this problem - I have found that if the outside cover is removed the furnace function normally. I have tested the sail switch and it seems to open and close properly. There is nothing visible to restrict tha combustion fan or the blower fan. Any ideas?

[rohrmann]

Do you have added bug screens on the outside cover? I have heard a few instances where those screens restricted the air flow just enough to cause a problem.

[Rebel]

There is no screens involved

[raygreg]

Originally Posted by Rebel

I have a similar issue with our 3812MS Montana in that the furnace fan will begin a cycle , run for a few seconds then shut down, control board indicates single flash (air flow problem) -- this is the second Montana we have owned that has had this problem - I have found that if the outside cover is removed the furnace function normally. I have tested the sail switch and it seems to open and close properly. There is nothing visible to restrict tha combustion fan or the blower fan. Any ideas?

Mine didn't start working until I removed the sail switch and manually activated . It tested good with a 0hm meter.
If it does it again , I am going to hook the sail switch wires together as a test to see if it will fire .

[Rebel]

Thanks

[ChuckS]

Hooking the sail switch wires together will not work..

The igniter module “has to see an open” condition first in that circuit that tells the module to run the motor to purge system and then when sail switch moves and completes circuit after purge time the igniter module will tell the ignitor to fire and propane valve to open...

You cannot clean the sail switch contacts so it is a temp fix if you don’t replace switch with a new one....

[hawkeye]

I have had to clean the jet on the burner tube . you have to remove the funance to do it,

[Theo]

For what they cost change out the sail switch
Had the same issues this past winter in Florida finally bought a new sail switch after many other things beeping check an reset
Sail switch fix it

[Dee_Dub]

Our furnace had the same symptom this fall. I pulled the furnace out. Sail switch was ok. Took the furnace to the local RV retailer and the furnace fired right up for them. Bottom Line..... bad propane regulator. A trick he taught me was to fire up your stove burners one at a time and see if the flame on the first one drops when the next one is turned on.

[beekeeper.va]

Sail switches are a common problem with intermittent lighting and stopping the furnace while running. The mfg used poor sail switches. If yours has a plain straight blade, you need to replace it with this one:
https://pdxrvwholesale.com/products/...l-switch-31094

[Khanscel]

We used these micro switches in the elevator trade and had problems with them at times. I modified mine by putting a lite weight piece of plastic on the side that the wind blows against on the-switch arm with a VERY GOOD EPOXY. It has worked for 4 years now. Just took it apart and cleaned blower blades this year and all looked well

[mleeder]

Place your hand over the exhaust port and let the furnace cycle. The back pressure will break the sail fin loose and should start.

[jjwhite368]

Check your 12v fuse panel. You may have a circuit breaker instead of a fuse. Our 2021 3121RL furnace would come on for a few minutes and cut off. After contacting our dealer he had me pull the breaker (which look just like a fuse except an opaque black color) and replace with a 20 amp automotive fuse. Problem solved. A picture of the circuit breaker is attached.