Intermittent furnace problem

[hatwate]

Originally Posted by 16ACE27

And you turn if "off and on" how?

On the thermostat where I choose cool, off, or heat. It’s on heat so I move it to off then back to heat. As soon as I move it back to heat, the furnace clicks on, goes thru it’s start up actions and heat is generated.

[16ACE27]

So you have an intermittent failure to light problem. After 3 attempts to light, the furnace locks out until reset either as you are doing it, or by the reset switch at the furnace itself. It fails to light due to either:

No gas - the propane valve fails to open
No ignition - a problem with the ignitor or gap
Improper air/fuel mixture - out of adjustment or bug/spider nest issues

I doubt it's a thermostat issue.
Since you changed the control board with no change in symptoms, it's probably not a control board issue.
Since it's intermittent, and works OK when cool, it may be heat related. If you want to fire the parts canon again maybe try replacing the gas solenoid valve and/or the ignitor.

Otherwise, disassemble the burner/ignitor and check for obvious issues (ignitor gap, rusty/disintegrating gas grate). The ignitor is also the flame sensor so it could actually be igniting the flame but if it fails to sense the flame after going through the ignition cycle 3 times it also locks out.

Here's an interesting video on troubleshooting a furnace issue. It's not your model furnace but the theory of operation is the same:

https://www.youtube.com/watch?v=aO8H33RFd-c

This one may be closer to your problem:

https://www.youtube.com/watch?v=AB69oqtSiwc

[hatwate]

Thank u

[Scubawise]

My bmpro control panel was bad. Called and software update fixed. Impacted AC & heat

[16ACE27]

Originally Posted by hatwate

Thank u

Let us know what you figure out the problem was.

[hatwate]

Thanks

[hatwate]

Originally Posted by 16ACE27

Let us know what you figure out the problem was.

Will do

[abjbrtd]

Don't forget the wire, cold temperatures WILL effect the wire

Another favorite (always hard to find) trouble is a lose or corroded ground.

[hatwate]

Originally Posted by abjbrtd

Don't forget the wire, cold temperatures WILL effect the wire

Another favorite (always hard to find) trouble is a lose or corroded ground.

Thanks!

[Chateau_Nomad]

I replaced our Coleman Mach analog thermostat with a basic residential Honeywell digital. I followed instructions from a YouTube channel "Love your RV" (Ray). It works perfectly... keeps temps within a couple degrees. Certainly beats the wonky and vague temp setting on the analog one.

A couple questions... Are the thermostat batteries fresh and fully charged? I use Eneloop rechargeables in about everything. Second... are you CERTAIN the replacement thermostat is wired correctly?

[hatwate]

Originally Posted by 16ACE27

So the fan is running and you don't get heat? Or the fan doesn't turn on?

Nothing is happening. No heat, no fan, nothing.

[hatwate]

Originally Posted by Chateau_Nomad

I replaced our Coleman Mach analog thermostat with a basic residential Honeywell digital. I followed instructions from a YouTube channel "Love your RV" (Ray). It works perfectly... keeps temps within a couple degrees. Certainly beats the wonky and vague temp setting on the analog one.

A couple questions... Are the thermostat batteries fresh and fully charged? I use Eneloop rechargeables in about everything. Second... are you CERTAIN the replacement thermostat is wired correctly?

As far as we know there are no batteries. The only certainty we have about the wiring is that it was professionally installed and at least one other RV service person checked it out

[Chateau_Nomad]

Here is a link to a basic troubleshooting guide for RV thermostats.

https://lifeonroute.com/is-your-rv-thermostat-working/

[hatwate]

Originally Posted by Chateau_Nomad

Here is a link to a basic troubleshooting guide for RV thermostats.

https://lifeonroute.com/is-your-rv-thermostat-working/

Thanks!

[Tiflog18]

There is a safety switch we have the exact same problem in our Vegas 24.1 it’s something to do with vapor vapor lock and it’s a known issue so you there’s a reset switch in your furnace vent cover I know it takes six screws to open it up. I am working with a friend of ours who has a really reputable mobile RV service in South Dakota. They should’ve moved that reset button inside . We found this while camping at fort wilderness two years ago

[Bill Johnson]

Originally Posted by hatwate

Thanks!

If the analog thermostat worked and the board has been replaced I wonder if the digital thermostat is not compatible with your unit

[hatwate]

Originally Posted by Tiflog18

There is a safety switch we have the exact same problem in our Vegas 24.1 it’s something to do with vapor vapor lock and it’s a known issue so you there’s a reset switch in your furnace vent cover I know it takes six screws to open it up. I am working with a friend of ours who has a really reputable mobile RV service in South Dakota. They should’ve moved that reset button inside . We found this while camping at fort wilderness two years ago

So once we reset it the problem totally goes away or it will continue to do it intermittently and we will need to reset every time? Is that essentially what I’m doing when I shut the furnace off and on to restart it?

[hatwate]

Originally Posted by Bill Johnson

If the analog thermostat worked and the board has been replaced I wonder if the digital thermostat is not compatible with your unit

We will double check but it is “supposed to be”.

[16ACE27]

Originally Posted by 16ACE27

So you have an intermittent failure to light problem. After 3 attempts to light, the furnace locks out until reset either as you are doing it, or by the reset switch at the furnace itself. It fails to light due to either:

No gas - the propane valve fails to open
No ignition - a problem with the ignitor or gap
Improper air/fuel mixture - out of adjustment or bug/spider nest issues

I doubt it's a thermostat issue.
Since you changed the control board with no change in symptoms, it's probably not a control board issue.
Since it's intermittent, and works OK when cool, it may be heat related. If you want to fire the parts canon again maybe try replacing the gas solenoid valve and/or the ignitor.

Otherwise, disassemble the burner/ignitor and check for obvious issues (ignitor gap, rusty/disintegrating gas grate). The ignitor is also the flame sensor so it could actually be igniting the flame but if it fails to sense the flame after going through the ignition cycle 3 times it also locks out.

Here's an interesting video on troubleshooting a furnace issue. It's not your model furnace but the theory of operation is the same:

This one may be closer to your problem:

Originally Posted by hatwate

So once we reset it the problem totally goes away or it will continue to do it intermittently and we will need to reset every time? Is that essentially what I’m doing when I shut the furnace off and on to restart it?

See quoted post above.

[Tiflog18]

Originally Posted by hatwate

So once we reset it the problem totally goes away or it will continue to do it intermittently and we will need to reset every time? Is that essentially what I’m doing when I shut the furnace off and on to restart it?

Its not a themrostat issue. Yes it needs to be reset everytime. Stay tuned