All drains running slow and grey tank empty

[DoubleVeteran]

Hi all,

I picked up a 2011 Roadtrek popular 190 last week and took it out camping this weekend. All the drains run slow (with the gray tank empty) and when I fill the kitchen sink with water (higher than the other drains) and drain it out, the shower and bathroom sink drains bubble and sputter water. Makes me think the roof vent may be clogged?

I looked at the vent and it's just a plastic pipe, uncovered, so I can see how maybe something may have gotten in there. I blew down it and there is resistance (should blow freely, yes?) and I hear water. I looked at the plumbing schematic and the pipe does not go straight down, but bends at a 45 deg (twice), so I don't see anything. Can I try and stick a water hose down there and try to flush it out?

Thnx!
DV

[loggenrock]

Glad I was able to help! ST

[Dick_B]

Thanks for the update. Too often posters state a problem, get various solutions recommended then silence from the poster.

[DoubleVeteran]

Hey all,

Issue solved....loggenrock hit the nail on the head 🙂

I was in the rig last night and the shower still had about 2 inches on water backed up on the shower floor. I removed the clean-out plug under the kitchen cabinet, heard a rush of air and all the water drained out! I removed the vent cap (also under the kit cabinet) and it does have a diaphram (anti-siphon?). I tested it and it seems to be working properly. Anyway, with the cap off, I tested the shower again and all flows beautifully.

Thnx all for the assistance!
DV

[mkguitar]

I have a PW- my shower drain is essentially right into the top of my grey tank.

We don;t use our shower and a have used teflon tape to seal the drain cap ( under pressure, ours too would bubble)...

I think that someone has hit the nail where you vent for the grey tank isn't venting properly
( on our model the grey vent is on the side of the van about 20" above the sink drain- it T's off under the sink)
with normal atmospheric pressure you should be draining fine with out an obstruction in the pipes



my black vent was also just a stub of pipe- a $20 Lippert 360º venturi causes a low pressure at the pipe with the slightest breeze- this has solved any odor problems esp when driving and opening a window ( in which case the van become low pressure and air can be pushed down the stub and gasses into the van).

Mike

[DoubleVeteran]

Hey, just a quick update on what I've found so far:

- With the gray tank completely empty, water from all drains flows freely, until the grey tank register's 1/3 full (23 gal capacity), then it starts to back up.
- the water backs up in the shower (lowest point drain). I sealed all the drains, except for the shower and took a plunger to the shower drain and the water slowly went down with lots of bubbles coming up from the drain.

At this point I'm thinking it is less likely to be a venting issue, and more likely maybe a clog somewherafter the shower drain to the grey tank? But, if that were clogged, it would flow slowly all the time, and not just until he grey tank is 1/3 full, right?

Anyway, I bought a small diameter plummer's snake and will try that tonight after work. There is a clean-out at the kitchen sink drain below the P-trap and I should be able to snake all the way to the grey tank.

Thoughts and advice is welcome!

DV

[My_Roadtrek]

Could be from hard water causing calcium build up in the lines.

[Islandman]

A liberal dosage of Dawn liquid dish soap will help clean drains too, could be just a bunch of garbage in the sink and hair particles in the shower drain. A guy from Michigan told us about this soap last year and it sure works fine.

[AJBert]

Sure you can. Don't be surprised if the water comes back out at you. I'd use a snake.

However, if all drains drain slowly, me thinks it is more likely a clog in the line between the last drain and the grey tank. You might want to pour some Draino or you choice of chemical drain cleaner before trying to the vent. Just my humble opinion.

[loggenrock]

Rooftop vent pipe is for black tank, or at least it was on our '03C190P. Look under the kitchen sink in the cabinet - should have a drain pipe with a venting cap (anti-siphon-something...) on it. Sounds like that diaphragm is stuck... ST