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brandss · 05-27-2022, 03:35 PM

Been chasing a smell in the coach while driving with a window open and it's lead me to these valves. In case anyone is wondering, I've changed the air admittance valves at all the sinks along with the check valve for the tank flush under the half bath.

Anyhow, question is if anyone has changed these valves. They are located behind the commode, inside the wood frame, and at the bottom on the floor. The commode and the wood frame will have to come out in order to get to them and looks like it's going to be a big job. Any tips would be appreciated.

DRM901 · 05-27-2022, 04:07 PM

Are you sure the new AAVs are working correctly.

The reason I ask is I went down the same rabbit hole in our 37AP. Replaced to both AAVs in our bath, the HepvO in the kitchen, verified the toilet seals were sealing, the toilet base O ring wasn't leaking, and ordered the check valve for the black tank flush.

When I had the MH into the repair shop for something else, I broke down and just asked them to fix it. They found both brand new AAVs were defective (or at least 1, but they replaced both).

You should be able to test them with a compressor on low psi.

ernieh · 05-27-2022, 09:22 PM

What do the valves inside the wall behind the toilet vent? Seems very odd.

Old-Biscuit · 05-27-2022, 09:39 PM

Hepvo Valves......water less traps used instead of standard 'P' traps

Basically a canister with a duck bill (bladder) inside that allows water to flow out then close off and stopping odors from coming back inside

Duck bill not closing due to debris/crud OR getting turned backwards

Should only be used on Grey water ...sink drains/shower drains

How do you know there are Hepvo Valves behind commode in the wood frame??

Plastic wrap around AAVs will quickly eliminate them

brandss · 05-28-2022, 05:12 AM

Thanks for all of the replies. I know the smell is coming from the rear, and I checked the new AAV's before installing. As old biscuit says, any crap in the duckbill and grey tank smell passes right through.

On our coach, or model, their is a "wood cabinet" behind the rear bath that houses the electronics and water valves for the toilet and when I take off the top, I can see the two hepvo valves on the floor. One is for the shower and the other for the washing machine. I was able to take the front off the shower base and see the drain going into this cabinet along with the washing machine drain.

Based on the amount of crap we pull from the shower to keep it draining, wifes hair mainly, I have to believe these are in need of replacement and there is no real way to clean them without going through this cabinet.

I think I will remove the commode and then start looking at what screws hold what regarding the cabinet, and go from there. There is a lot of "stuff" in this small cabinet so pictures to help remember what goes where is in order. Wish I could replaced the hepvo valves with j traps like I did in the kitchen sink but don't see a way since they ride all along the floor of the coach.

thegats1 · 05-28-2022, 05:14 AM

Quote:

Originally Posted by ernieh

What do the valves inside the wall behind the toilet vent? Seems very odd.

Just when I thought I was finally getting a clue about RV's. Keep learning new things. Just watched a video on how it works. I too am curious what the valves in the wall behind the toilet are. A vent line to the roof? Not sure why that would be valved and why the smells would enter the coach. But, since I didn't know what a HepvO was, maybe I am missing something else.

Peter M · 05-28-2022, 06:12 AM

I have changed said valve on my 32 SA shower. I confirmed this was the problem by placing a wet rag over the shower drain. The rag sealed and blocked the grey tank gas confirming the problem. Tight working quarters, after bleeding knuckles job complete.
Note: When reattaching fittings I used Teflon tape on the threads to assist with reducing thread resistance when joining the union.
Good Luck!

garykk · 05-28-2022, 10:34 AM

Have you tried a good drain cleaner on the HEPVO? I treat ours several times a year and so far no smells, drain is clear.

Old-Biscuit · 05-28-2022, 12:18 PM

Cleaning
No routine or seasonal maintenance is required for the HepvO sanitary waste valve, however, should you blow-out your drainage lines do not exceed 80-100 psi.

HepvO is resistant to standard caustic-based drain cleaners.
It is also resistant to acid-based cleaners with concentrations up to 10%.
*When flushing with higher concentrations of acid based cleaner, the valve must be removed before the operation.

*If mechanical drain cleaning devices are to be used it is necessary to first remove HepvO from the waste system.
This provides a useful access point for servicing downstream pipework.

It is good practice to rinse the HepvO valve with clean water after any maintenance procedure.