Sewage smell!!!

[Double R]

Down in sunny Florida, but it’s going down to the 40’s at night. So we are using the furnace. There is a sewage smell coming from the heat vents obviously it’s coming from the black tank. Have no idea why or how to prevent it. Have had tank full and empty same smell. Any suggestions or thoughts would be appreciated. Thanks in advance.

[K0LCB]

Where is your black tank located in relation to your furnace?

[Double R]

Just in front and above it.

[K0LCB]

Your black tank is in front of and above your furnace?

[Double R]

No the furnace is in front of and higher than the black tank

[10scDust]

Is it sewage smell, or more like dead mouse?

[Joe-FL]

What make/model do you have?

[mcr1010]

Just a swag here, but if the smell occurs only when running the furnace, maybe you are pulling a negative pressure inside which will pull make up air from your tank vents. Sometimes the culprit is the vent under the bathroom sink that ties to the black tank. You can open a roof vent or window while the furnace is running and see if that eliminates the smell. If you feel an inrush of outside air it may be a tip off also.

[Double R]

I’ll try that thanks

[Muggs]

Whenever we park or I empty tanks we refill all sink/shower traps. If last thing done was draining tank, the vent is not big enough and it will pull all water out of traps. I believe makeup air for furnace is inside coach.

Furnace is air to air heat exchanger and all hot side is outside coach. Also dead frog, lizard or mouse in vent/ducts can create terrible smell.

We are in central Florida and on recent trip to NC (snow) it was raining dead tree frogs from under coach. They stink pretty bad for a short time.

[Bob Denman]

I swear: I've never visited your rig! Honest!

http://www.thorforums.com/forums/att...1&d=1548164820

[K0LCB]

If it is really smell from black tank, I would suspect a loose seal aroun the down pipe from your toilet stool to the black tank.

[Bob Denman]

I agree: There's no direct connection between the two systems...
But since the heater is ducted so as to throw heat on the tank: some stray fumes might find their way back upstream.