Plumbing

Freddy · 08-07-2006, 04:21 AM

On Sheet 2 of the following drawing, is the part marked VM-1 under the kitchen sink a vacuum breaker?

It seems to be the source of the strong sewage odor that we sometimes get in our coach.

http://www.winnebagoind.com/diagram/...f34d_plumb.pdf

Freddy · 08-07-2006, 04:21 AM

On Sheet 2 of the following drawing, is the part marked VM-1 under the kitchen sink a vacuum breaker?

It seems to be the source of the strong sewage odor that we sometimes get in our coach.

http://www.winnebagoind.com/diagram/...f34d_plumb.pdf

Joe-K · 08-07-2006, 05:05 AM

Freddy,

It is a drain line vent.

Ours was the cause of an odor in the motorhome as well when it broke. The vent has a small rubber disk in it held closed by light spring pressure. It's purpose is to allow air to enter through the vent when there is strong suction in the drain line that would otherwise pull the water out of the sink trap.

What happened in ours, is the rubber disk wasn't sealing so we would get odor. The vent just unscrews from the drain pipe and was available at my local home improvement store. If I recall, you're looking at 4 or 5 dollars for the replacement.

Below is a picture of typical undersink plumbing, and a closeup of the vent so you can look for it at the store.

dawg · 08-07-2006, 05:07 AM

I would bet that is the problem. I have replaced mine twice. Under $5.00 at a home supply store.
(I did not look at page 2)

Tom N · 08-07-2006, 06:10 AM

Yes, VM-1 is a vacuum break. If you have to replace it you should be able to get one at Lowes or Home Depot.

Tom N · 08-07-2006, 06:22 AM

Nice photos Joe!

I did not know that these unscrewed.

Joe-K · 08-07-2006, 06:32 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Tom N:
Nice photos Joe!

</div></BLOCKQUOTE>

Thanks

but I got to admit, I didn't take them. I found them on a plumbing website. There's always questions about the vents so I thought the pictures would help.

smlranger · 08-07-2006, 06:45 AM

There is one of these gizmo's in our rig that is for the W/D drain, so it's behind a chest of drawers in the bedroom. We don't have the W/D but I believe it may be a culprit in a case of smelly gas for which I frequently get blamed

. I do try to blame the dog whenever I can

.

Freddy · 08-07-2006, 12:10 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by smlranger:
I believe it may be a culprit in a case of smelly gas for which I frequently get blamed

. I do try to blame the dog whenever I can

. </div></BLOCKQUOTE>

Me too!

He doesn't get blamed as often since we began to notice the smell around the undersink area.

Thanks all for the tips and esp. the photographs.

Freddy · 08-07-2006, 01:22 PM

I just took mine off and the seal is tight. I didn't find any crimps or folds that would provide a leak area. The odor inside the cap was similar to that of the stuff I use to "sweeten" the odor of the gray tank.

The vent wasn't screwed in very tight, so that might have been the cause. But, I'll buy one next time I'm at one of the home box stores.

Right off I don't see a path from the black to gray water tank that would allow sewage odor to back into the gray, then to the sink. The only apparent path is when both black and gray discharge valves are opened at the same time.

Clay L · 08-07-2006, 02:46 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Right off I don't see a path from the black to gray water tank that would allow sewage odor to back into the gray, then to the sink. </div></BLOCKQUOTE>
Do you have two vent pipe outlets on the roof?
I ask because my floorplan has a "Tee" and the black and grey are connected to one vent pipe going to the roof.

Freddy · 08-07-2006, 03:06 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
Do you have two vent pipe outlets on the roof?
I ask because my floorplan has a "Tee" and the black and grey are connected to one vent pipe going to the roof. </div></BLOCKQUOTE>

I was up there this morning and noticed two vents. One is located on the left side, and one to the right, nearly all the way across the coach.

Presumably, the one on the left is off the black tank, and the one on the right is off the gray water tank.