Furnace black smoke

[Holiday27]

Hi All,
Hoping I can get some furnace help. With searching I had no luck.... When I run my furnace I get stinky dark smoke. Here's the weird part. I pulled it out and bought the proper connectors and hooked it up to my car and a propane tank and it ran fine. My fridge and stove work well. Do I have an issue with my propane regulator on my RV though? I don't understand why the furnace runs dirty in the RV.

Anyone have any ideas? Thank you!!

[Holiday27]

BarabooBob wrote:
When you find the problem and solve it, please let us know the solution to your problem.

For sure!

[BarabooBob]

When you find the problem and solve it, please let us know the solution to your problem.

[Holiday27]

Yes, I connected to a fresh 5 gallon portable tank with no change.

I haven't been using it for the last couple years as we rarely camp in cold weather and if we do I have a catalytic propane heater I can break out.

I'm an engineer so it's in my DNA to problem solve and fix but hasn't been on the top of my list.

[bobndot]

Did we cover this already ? The LP gas ?
It might be bad Lp. Depending on how the last lp supplier maintained his eq , could mean his contaminated lp, contaminated your tank.

Might now be the time for a pro lp tech to come in. This could be a dangerous situation . Don’t use it !

[Holiday27]

bobndot wrote:
This vid shows cleaning an rv furnace.
Cleaning out baby birds. Thats right… birds ! The kind with wings . :B

https://youtu.be/Z0RTlwg0PGk

When you wash your rv , make sure you don’t spray water into the furnace vents. I would think that would cause some rust.

Im still thinking an air inlet issue.

Interesting video, pretty messy in there. Wish mine was that simple. No issues with air inlet that I could see and burner looked great.

When running the flame sounds like it has a slight flutter and you can see a slight amount of smoke, smells terrible.

https://flic.kr/p/2oCfxfH
https://flic.kr/p/2oChwD2

[bobndot]

This vid shows cleaning an rv furnace.
Cleaning out baby birds. Thats right… birds ! The kind with wings . :B

https://youtu.be/Z0RTlwg0PGk

When you wash your rv , make sure you don’t spray water into the furnace vents. I would think that would cause some rust.

Im still thinking an air inlet issue.

[Holiday27]

BarabooBob wrote:
Do you happen to have a screen on the furnace intake/exhaust area? If it is too fine of a mess, it could restrict air intake.
I am sure that you have a restriction somewhere on your air intake. This would result in a rich mixture that causes smoke.

I do not. Checking burner later but it's pretty new. Maybe 5 years old with little use.

[BarabooBob]

Do you happen to have a screen on the furnace intake/exhaust area? If it is too fine of a mess, it could restrict air intake.
I am sure that you have a restriction somewhere on your air intake. This would result in a rich mixture that causes smoke.

[bobndot]

I’m thinking air mixture.

#8 on the link shows info with pics.

https://rventhusiast.com/rvexpert/furnace-follies/

Hope this helps.

Bob

[Holiday27]

Tried an external tank, no change. Checked voltage and getting 12 volts at on/off switch and 11.2 at the power junction. I'm going to pull the burner tomorrow. The flame sounds erratic.

[Holiday27]

bobndot wrote:

Holiday27 wrote:
I replaced the regulator and still have the same issue. So frustrated. Could low voltage cause this?

First thing to know.
When you pulled the furnace out to test it outside of the rv, did you use the same 12v power source or a different power source ?

There is a link that i saved that might be worth a read. It might cover something you missed.
It covers outside and inside furnace operation.

https://www.rvtravel.com/ask-dave-furnace-functions-irregularly-rvdt-1733/

Thanks! I'll check it out.

I connected it to my car and a BBQ propane tank. It ran great. That's why I'm thinking possible voltage issue. Later tonight I'm going to try to run it with and external propane tank to eliminate that as an issue...

[bobndot]

Holiday27 wrote:
I replaced the regulator and still have the same issue. So frustrated. Could low voltage cause this?

First thing to know.
When you pulled the furnace out to test it outside of the rv, did you use the same 12v power source or a different power source ?

There is a link that i saved that might be worth a read. It might cover something you missed.
It covers outside and inside furnace operation.

https://www.rvtravel.com/ask-dave-furnace-functions-irregularly-rvdt-1733/

[Holiday27]

I replaced the regulator and still have the same issue. So frustrated. Could low voltage cause this?

[klutchdust]

After changing out the propane tank once I turned the valve on the tank quickly and It triggered a valve that was built into the fuel line and stopped the flow of the gas . What a time I had figuring that one out.
Also spider webs can interfere with fuel flow. I had that issue recently and my water heat was acting erratically, blowing black smoke. I just ran it on electric until I got home.
Normally before each trip I use compressed air to clean out the fridge chimney and fuel chamber and water and furnace tunnels.