What is this nob on the roof

[tomx]

I noticed there is a black nob on the roof of my 2006 Roadtrek 170 popular. Does anybody know what it is for? Thx!

You can see the samll black nob on the left side of the picture attached. I think it is right above the bath room.

Tom

[dougbaty]

Originally Posted by tomx

I noticed there is a black nob on the roof of my 2006 Roadtrek 170 popular. Does anybody know what it is for? Thx!

You can see the samll black nob on the left side of the picture attached. I think it is right above the bath room.

Tom

Judging by its location above the commode and by its appearance, it must be the top of a vent tube for your black water tank. When you flush and water goes in, air has to come out. The cap on top prevents rain from entering. Unpleasant smells are blown away as you drive, ventilating the black tank and reducing odors.

BTW, your sink - and by extension your grey water tank, also must be vented. To reduce holes in the roof the vents for both grey and black tanks are often combined.

DougB

[VTPete]

Doug is correct. Like any septic exhaust vent, you may notice on cold mornings a sewer smell when you push water into your tanks... septic gases are heavier than air and although they vent to your roof, they can sometimes sink back down to your nose.

[BBQ]

.

I thought methane gas is lighter than air. No?

[gregmchugh]

There is no cap on Roadtrek vent pipes...

[Hondo]

I Installed a 360 Siphon Vent onto the open plumbing vent. The vent cover will not only help draw away odors while moving (venturi effect)
it will also keep out foreign objects (the silver maple tree that is near the Roadtrek 210 drops seeds & buds all over it).

Before, open to the elements -



And after installation- a little silicone held it in place-

[VTPete]

Originally Posted by BBQ

.

I thought methane gas is lighter than air. No?

Aha! You got me, there! Methane IS lighter than air, but all those other stinky gases in "septic gas" aren't. I had to go Google it!

-Pete

[rickhoran]

Originally Posted by tomx

I noticed there is a black nob on the roof of my 2006 Roadtrek 170 popular. Does anybody know what it is for? Thx!

You can see the samll black nob on the left side of the picture attached. I think it is right above the bath room.

Tom

Are you sure it's not the GPS antenna?