Roof Vents

[TheNescios]

Have been dealing with an odor problem primarily from the forward black tank area that appears to come from the underside of the RV. It's been an on/off again type of issue which has gotten worse with warmer weather here in the Pacific Northwest. Do a very thorough rinse when I flush the black tank and run the internal spray unit until the only thing that comes out is clear water, then follow it up with draining the gray tank.

Have done all the normal looking with a flashlight behind the garage walls and no signs that the black tank is leaking or any fittings are not connected - best I'm coming up with are the vents on the roof needing an upgrade?

One of the solutions I'm considering is swapping out the roof vents for something that promotes more vented airflow - both Lippert & Camco make interesting looking units, leaning towards the Lippert as there woudn't be any moving parts which I like the idea of.

Input on what others have exeperienced and done to resolve this issue welcomed!

[Cate&Rob]

Hi Chris,

Where exactly are you detecting the odour?

Rob

[Jlawles2]

Chris, is the odor inside the unit or outside? Have you looked at the coroplast to see if it has a downward bulge in it that could be from a cracked black tank leaking into the underbelly?

[TheNescios]

Odor is primarily outside and down low when standing or sitting in a chair.
Coroplast doesn't show anything more than what I think are a few very minor sags from the distance being spanned?
And it's not consistent - sometimes it occurs when the tank has been freshly drained & flushed, other times when it's getting close to being emptied.
Warmer weather seems to make it worse, but even that's not consistent.

I'm also having a kitchen sink that seems to drain a bit slower than it used to - checked the trap, no obstructions, replaced the vent next to the sink - no change.
Started thinkinga about the roof vents and whether a better vent might provide better air movement for both gray & black.

Only time I get odor inside is when the room vent fan is running and the toilet is flushed.... and there just isn't any cure for that situation that's practical or cheap. (that I know of?)

[Jkwilson]

Check your battery. When a lead acid battery fails, it can emit a rotten egg smell when being charged.

Roof vents are for the tanks, and likely won’t restrict the sink drains all of the time, even if clogged. The AAV is the vent for the fixture drains and can cause immediate problems if bad.

[TheNescios]

Hadn't considered the batteries, typically they're more of a sulfur smell from my experience.... but it's been 4-6 weeks since I checked on them so will do do that later today.
Still thinking about upgrading the roof vents - and like the looks of the Lippert one that's fairly open vs the factor ones.
The Camco one that swivels is a great idea in principle, but the need to move to be effective goes against my Keep It Simple Stupid principle - anyone have any feedback on changing the vents out?
Other part of this is I'm not a fan of heights so every time I have to get on the roof of the RV it's not much fun so try to do it right the first time.

On another note, when flushing I not only have the clear 90 down into the dump connection, but added the clear 45's (have 2 gray/2 black tanks) coming out of the RV after the auxillary dump valve that I added (saves on the drips & leftover fluid when hooking & unhooking the hoses per a posts I read on here when we first got the 5th wheel) to monitor how the flushing is going. Makes it so much easier to monitor whether it's a steady clear flow or not plus helps make a nice transition down to the sewer hose supports. Once it runs clear and steady I close off the gray tank and let the flush water run for 2-3 minutes to put a nice "base" of water in the tank.
Saw on another post where someone mentioned pouring a 5 gallon bucket down to elinimate any "cone" buildup - this is something else I do every once in a while "just because" - think it was that post that also mentioned getting black tanks fixed once there is an issue can be challenging, better some extra preventitive care than issues.

Appreciate the feedback on venting - makes it easier figuring out issues with shared experiences!