What is this thing on the roof?

[Old-Biscuit]

Originally Posted by keymastr

Black tank vent. Gray tanks vent through air admittance valves under sinks.

And will have vent line to roof...pretty standard set up

AAV on sink drain lines are to prevent 'P' traps from getting sucked dry when drain grey tanks. They open from negative pressure created by the draining.


My 5th wheel has black tank vent with cap, grey tank vent with cap, galley tank vent with cap and both sinks have AAVs downstream of 'P' traps

[JIMNLIN]

A roof jack for a a vent pipe is another std part that can be found at most rv dealers store or a mobilehome/rv parts dealer around town.
Like OEM the usual butyl tape under the flange for first line of defense for water intrusion....scr'er down and use a self leveling sealant product like Dicor over the scr heads and edge of the flange as the 2nd line of water intrusion defense.
I've used them over smaller holes in the roof .

[98fleetwood]

Originally Posted by barefootewok

Hi all - Happy 4th of July

While on the roof of my friend's Trail Bay 3000 Series 529BHSS fifth wheel, I kicked this plastic thing and put a hole in it. It's very brittle. I'd like to replace it or hire someone to replace it.

Does anyone know what it is?

It's right near the front of the refrigerator vent cover.



Also, I put some Dicor self-leveling sealant over the hole. Later, I realized sealant might fall into the hole since it's "self-leveling". If that happened, could it cause any problems?

It's a plumbing vent.. kinda like the black ones that stick through your house roof.. they are very inexspensive..

[TRNewsom]

Air admittance valves only let air IN. As water fills the tank, air must come OUT. That’s what the roof vent is for.

[Old-Biscuit]

Originally Posted by TRNewsom

Air admittance valves only let air IN. As water fills the tank, air must come OUT. That’s what the roof vent is for.

Short, sweet, right on point

[Ljwt330]

Originally Posted by barefootewok

Eez Moose, I appreciate your suggestion. The 5th wheel is going to stay parked on some acreage. The black tank won't be used and the grey water should flow directly to the landscape (to a mulch pit or some responsible location). So, I don't think a fancy vent will be needed.

David Jay, thanks for your suggestion. I gooped it up good!

Does anyone know where to buy a vent like the one Ljwt330 posted?


If not, I am leaning toward one like this:

The one I posted is made by Camco and is easily found at most RV supply stores and certainly on line.

[MSHappyCampers]

I would use this one!

https://www.amazon.com/Lippert-Compo...%2C261&sr=8-17

[Nlambert]

Originally Posted by barefootewok

Eez Moose, I appreciate your suggestion. The 5th wheel is going to stay parked on some acreage. The black tank won't be used and the grey water should flow directly to the landscape (to a mulch pit or some responsible location). So, I don't think a fancy vent will be needed.

David Jay, thanks for your suggestion. I gooped it up good!

Does anyone know where to buy a vent like the one Ljwt330 posted?


If not, I am leaning toward one like this:

Did you just crack the cap itself, or the tube that the cap attaches to? I broke one of my caps the first time on the roof and replaced it from the parts department at the dealer for $8 the same day.

Amazon and just about everywhere sells the caps. They're just held on by a spring that bites the inside of the pipe. Very easy to swap if it's just that piece.

[kdauto]

I've seen those rooftop tank vents on Amazon for as low as 11 bucks. I'd just use stock one. Moving things will eventually wear out and get loose or break off and leak. There's not uch rocket science behind tank venting. If it smells bad, it's been full too long or someone isn't using the deodorizer stuff.

[barefootewok]

This is my 1st post here and I gotta say there are so many helpful folks here!

Ljtw330 - Thanks, I found one that looks just like that and ordered it.

Nlambert - I cracked the base of the vent cover, so I gotta replace the base and the cap. I imagine the vent pipe itself is fine.

Thanks, all

[Winemaker2]

Easiest way to reduce the chance of that happening again is to put a coat or two of spray paint on the new vent. Bare plastic will be attacked by UV a lot faster than with a coat of white paint.

[09 harley]

Look at the 360 vent model. Great air flow