Community Forums

JEY1950 · 02-22-2019, 04:15 AM

I have an Allegro (2012) Open Road (TGA 34) that has an odor that seems to be coming from the shower drain - we've tried several deodorizers and several flushes to no avail. Someone suggested we might have a clogged gray tank vent pipe and to run the water hose down it to get it unclogged. We did that and it seems just fine. Anyone else with this type of problem - how was it remedied?

Lv2Roam2 · 02-22-2019, 04:23 AM

Might be a bunch of gunk - a solution of bleach and water with a liberal flush should help. If the drain is slow use a drain clog remover/cleaner first ...

Pigman1 · 02-22-2019, 10:35 AM

Are you sure it's a gray tank and not a black tank odor? We and others have had problems with the black tank flush vacuum breaker feeding odors into the coach. Seems Tiffin used a cheap, plastic vacuum breaker that sticks, venting sewer gasses into the coach, especially when you first start to drive. Heavy duty brass valves are readily available as a replacement on line.

Persistent · 02-22-2019, 10:54 AM

Quote:

Originally Posted by Pigman1

Are you sure it's a gray tank and not a black tank odor? We and others have had problems with the black tank flush vacuum breaker feeding odors into the coach. Seems Tiffin used a cheap, plastic vacuum breaker that sticks, venting sewer gasses into the coach, especially when you first start to drive. Heavy duty brass valves are readily available as a replacement on line.

The same thing can happen with the gray tank. P traps are used to block air coming back up a drain pipe. Every P trap needs a vent. When it is not convenient to vent through the roof, builders add vacuum breakers. Open vacuum breaker or plugged vent can cause the problem.
Also build up of hair and stuff can prevent the P trap from filling with water properly allowing gas back up. We had this in our home bathroom once.

Old-Biscuit · 02-22-2019, 11:02 AM

How does shower drain??

Does it drain quickly, normal
OR
SLOW

Slow..clogged/obstructed drain or vent
Normal..then 'P' trap is working and so is Vent

Check inside bathroom sink cabinet for an Air Admittance Valve on sink drain line after the 'P' trap.
AAVs open when draining grey tank so sink drain line does not have a negative pressure created which will suck 'P' trap(s) dry (many sink/shower share same drain line to tank)
AAVs stuck open will allow grey tank odors back inside RV....grey stinks

Peter M · 02-24-2019, 07:50 AM

My 2017 32 SA had a defective trap in the first 6 months of use. The shower does not have a P trap, it has a inline membrane trap. Open the access panel to the shower and you will see it. Be prepared to skin your knuckles performing replacement.

One way to confirm source or temporary mend the issue. Saturate a rag or paper and lay over drain to block the stinky emissions.

Picture view of the elbow attached to the trap behind waterlines.

Roger G · 02-24-2019, 09:37 AM

It very well could be the check valve on the drain but I would change the air admittance valve under the sink first just to make sure that isn’t the source of the smell. It’s difficult to trace a smell in a small place like a bathroom. The air admittance valves are very inexpensive at Home Depot or Lowe’s.

sialb · 03-04-2019, 09:43 AM

In our case we had a leak in the drain pipe. Look for water in one of your storage compartments. This leak eventualy saturated the floor under the tile. Bad news

garykk · 03-04-2019, 10:57 AM

If you have a drain setup like Peter M, then you have a HEPVO valve for a drain. Most likely it’s stuck open due to hair and or soap scum. You can use drain cleaners on these drains but not mechanical systems like a snake as it will damage the membrane.
Do a search on HEPVOs and you can download the info on them for cleaning and setup.
Our previous MH had HEPVOs and I used Draino on them frequently to keep them flowing smoothly.

Peter M · 03-05-2019, 05:01 AM

Good PM information Gary.
The rubber membrane flaps on my Hepvo valve would not close creating the failure. Similar to a varicose vein.

shaneotr · 09-05-2019, 02:16 PM

Our 2015 Suncruiser has a HepVo type filter on the shower drain and while driving sewer gas was gagging! We took out the filter to find the membrane had been sucked back thru and was open. Not sure how that happened, but I cleaned the filter and fixed the membrane, reinstalled the filter and now we'll see if it works or if we have to replace the whole filter. Kinda wondering if the air pressure while driving caused the displacement of the membraine. Anyone know if that's possible?

The smell was definitely from the shower drain. If I cover it while moving, all is well. When we stop the smell is gone. Sure hope we fixed the problem. Our tanks are empty and we always use cleaner...didn't seem to help the smell!

brandss · 09-06-2019, 09:36 PM

The smell in the coach we had only occurred while driving down the highway with a driver and passenger window open. We changed out the traps, air admittance valves, everything. After that, we found some relief.

What we finally did to solve it all, and I am not one to tell you that there is a cure all to anything, is started using happy campers in both the black and grey tanks, every time we dumped them. We read the reviews, kind of hoped it would work, and let me say, it solved every odor problem we have ever had.

Again, I don't do reviews or hype products but damn, this stuff simply works. There is some sort of chemical reaction with the Happy Campers and when it is mixed with water (we use a cup to mix it with water before pouring it down the drain) and the darn cup gets hot.

We will from now on add HC to both tanks every time we dump them.

shaneotr · 09-07-2019, 04:41 AM

Thank you for the info, I will definitely find some HC. I also discovered that the waterless trap membrane had been partially opened. We took it out, cleaned it and put the membrane back in place. I am fairly certain that was the source of the sewer gas smell. Why it was partially sucked back toward the drain causing it to not work properly is yet unknown. We will replace it if that happens again. We have a cyclone vent cap so why there may still be unequal air pressure while driving may be the ultimate problem. We shall see!