2018 Vista 27PE Sink "P" trap question?

mikee409 · 05-05-2020, 07:06 AM

This is a new class A we bought a few months ago and are just now getting to spend some time using it.

Can anyone tell me if there is a "P" trap below the floor in the bathroom?
I looked under the bathroom sink and there is not one there where it should be. The kitchen sink has one so why not the bathroom sink?

The problem is we are getting a bad smell from the bathroom when traveling.

This smell is not from the toilet it's holding water on top of the flush valve, and the roof vent fan hatch is closed so I know it's not pulling the smell in from outside.

At 1st I thought the water had evaporated in the trap so I poured some in the sink. I could hear the water running into the holding tank thru the shower stall drain? That's when I looked under the sink & saw no trap?

Now I'm wondering if it's just shoddy workmanship or there is supposed to be a common "P" trap below the floor & above the holding tank. It sounds to me like it's just running straight into the gray water holding tank

Thanks for your input. Mike

mikee409 · 05-05-2020, 07:21 AM

I found this part in a plumbing diagram for my 27PE Vista.
TRAP-WATERLESS,1-1/2"
165406-01-000
It's common to the sink and the shower drain.

So has anyone else had this odor problem besides me?
What did you do to fix it?
Mike

**creativepart** · 05-05-2020, 07:24 AM

Congrats on the new RV!

It’s possible you have one of those waterless traps traps installed. They are getting more common in RV bathrooms to save space under a bath sink. They don’t look like p-traps.

As to the gray water smell I’m not sure. We get that in our 1/2 bath occasionally but it goes away so quickly and is so infrequent that I’ve not tracked it down.

Morich · 05-05-2020, 09:12 AM

Looks like another try to reinvent the wheel and solve a very simple problem with a very complex solution! This does not appear to be something I would want to be among the first to use! Experience with looking at the inside of drains, makes me think this is a very short term solution and I hope the put it in a place where it is easy to access. As it appears to be really hard to access in your unit, I might first look at simple ways to try to clear the problem as I see lots of good chance for it to stop working as soap and/ grease look likely to stop the funcion.
My first thought would be to try some of the bacteria as used for septic tanks and hope that it would eat the scum off the new P-trap enough to allow it to fully close. Not a good shot in my view but also much easier than the second thought. Scum builds quickly at times but clears slowly. I have used the bacteria and found it does do a good job of cleaning the inside of drains- -but slowly if not used full time.
Second thought would be that a traditional P-trap might need to be installed at each point of use.
These are just my thoughts and certain to be open to change but the idea of placing a membrane in a drain and expecting it to allow flow and then reseal to airtight is just really hard to imagine once you have seen the inside of a drain! There's nasty slick stuff in those I've checked!

mikee409 · 05-05-2020, 10:04 AM

Morich, Thanks for the reply.

I agree with the fact it's a short term solution bound to malfunction. I guess it's the new generation of engineers that are trying to reinvent the wheel.

I plan on installing a real "P" trap under the sink and putting a rubber pad over the shower drain to close it off during non use/ travel times. If the pad doesn't work I'll remove the pipe cover from behind the sink & toilet & install a quick open valve to the shower drain pipe section with easy access to the handle & close it off for sure when not using the shower.

Poor design at it's best. I/you would think Winnebago would have by this time figured out the most fool proof ways to build an RV since they have been around/ in business for so long : (
That was one of the main reasons for purchasing a Winnebago to start with.

I'll add some of the crud eating stuff to the line for good measure & start rounding up parts for the "P" trap install.
Mike

**creativepart** · 05-05-2020, 10:28 AM

Waterless drain traps have been around for quite a while and are used on huge numbers of RVs. They've proven to be good designs and in fact many reviewers prefer them to p-traps.

Just because it's new or different doesn't mean it's ill conceived or poorly designed.

When Bell invented the Telephone people wouldn't hold the thing. When Edison invented the light bulb there were people that wouldn't enter a house with light bulbs they wanted the good old safety or a raw flame and odorless natural gas.

PS. I'm still a kid, but I'm 70 years old.

mikee409 · 05-05-2020, 07:50 PM

Creativepart, All I know is It doesn't work in my situation. Our previous RV a 2001 Dutchstar had old school P traps that never failed. I'm open to change but sometimes old school is better.
Nice to hear from a fellow Texan. Were about 2-1/2 hours East of you on the TX/LA border.

**macnut** · 05-05-2020, 08:01 PM

Sometimes the waterless p traps go bad, but rarely. If so, they are easily replaced as they simply screw on and off. I have also seen previous threads that sometimes the vent pipe to the roof is not connected properly, leading to bad smells inside the RV. I would check the vent pipe to see if it’s glued tight. Best of luck to you!

jcr5353 · 05-05-2020, 08:16 PM

I found the same trap in mine when I noticed no p-trap. Have not noticed any odors at anytime, driving or stationary. If you haven't used the sink/shower for awhile, the "flapper trap" may just be dried out some. Odor only while driving is odd for sure.

Note: If you fill the sink with water, and then release the water quickly by pulling the plug, some water will back up into the shower. Important if you stow anything in the shower stall while not in use.

**creativepart** · 05-05-2020, 09:43 PM

Quote:

Originally Posted by mikee409

Creativepart,

Mike, I think you may be jumping to a hasty conclusion that is not necessarily what's causing the smell problem. Could it be? Sure. Is it likely? Not so much.

Adven2011w24 · 05-11-2020, 09:42 AM

I have a 2011 Winnebago 37f and I had a terrible smell in my half bath after driving caused by the low pressure created by driving with a window or a vent open. After a lot of Investigation it turned out that the vacuum check valve that's located above each P-trap were leaking. They we're of the non spring-loaded type and had relaxed overtime and allowed the smell to come in the RV. I went to Home Depot and for about $6 each put in new ones and I haven't had any odor sense. The new ones have a real light spring and seemed to work fine. The four locations are the kitchen sink the half-bath the rear bath and the washer dryer area.