Garage Shower 397 TH

[awheeladventure]

I noticed today that the garage shower in my 2019 Mo 397 would overflow when refilling the black/gray tank with fresh water after dumping. I only filled the black/gray tank for 3 minutes after dumping to give it a more thorough cleaning. I’ve wondered why there always seemed to be an odor in the garage bathroom. Now I see why it does. In my opinion, the garage shower is worthless in the 397 and the space should have been used for cabinets as some other owners have modified theirs.

[Country Campers]

Depending on the usage a full bath with only one tank can get filled pretty quickly. If the toilet is used the most make sure that there is plenty of water to start, not enough water will cause a build up of solids.

Not sure if you are looking for help or not.

Brian

[awheeladventure]

Looking for some suggestions on controlling the odor coming through the shower drain from the tank. Also was venting about how useless the shower is unless you’re a small child.

[howson]

Looking for some suggestions on controlling the odor coming through the shower drain from the tank. Also was venting about how useless the shower is unless you’re a small child.

Based on the info GD has made available to the moderators, in the 397TH the rear bathroom shower drains into the same gray tank as the kitchen sink. (The bathroom's lav drains in that gray, too.) The tank exclusively for the rear bathroom's toilet is (obviously) a black tank.

Focusing on the smell coming out of the shower, I suspect it is a faulty air admittance (AAV) valve. There are three on this one tank--one each for the sink, shower, and lav. Good thread on the topic here: https://gdrvowners.com/forum/operati...mittance-valve

Howard

[Cate&Rob]

The drain on your shower likely uses a Hepvo one-way valve https://hepvo.com/hepvo-waterless-valve/ rather than a conventional P trap. If this “duck bill” valve is damaged or held open, it will allow tank odour back up through the shower drain.

Rob

[howson]

The drain on your shower likely uses a Hepvo one-way valve https://hepvo.com/hepvo-waterless-valve/ rather than a conventional P trap. If this “duck bill” valve is damaged or held open, it will allow tank odour back up through the shower drain.

Rob

Rob--the drawing shows three "anti-siphon valves" connected to the tank where the shower drains (as noted in the post above). Could this be either an AAV or Hepco? On the 315RLTS a Hepco is referred to as a "ventless trap" (I think).

[Cate&Rob]

howson

An AAV could be termed an "anti siphon valve" since its purpose is to allow air into the drain system to prevent water dropping down the main drain from pulling the water out of the P trap. This would not be required with a Hepvo "duck bill" valve in the drain pipe. So . . . perhaps the rear shower in question has a P trap rather than a Hepvo? Since the reported smell is coming from the shower drain, this would be caused by a Hepvo stuck open or potentially an AAV stuck closed allowing a P trap drain to empty out. To add one more level of confusion . . . an AAV is only required if there is not a nearby vent stack through the roof. Is there a separate vent stack for the rear bathroom?

Rob

[howson]

Is there a separate vent stack for the rear bathroom?

According to the drawing--yes. Partial shown below (I think the powers-that-be won't mind this partial drawing being posted.) Note that "11" is a reference to an AAV.