Pros and Cons for the Removal of Black Tank Flush Relief Valve

[Speedy]

I'm in the process of moving my water filters inboard and cleaning up all the water lines behind the UDC and I would like to know the pros and cons for the removal of the black tank flush pressure relief valve.

I have two reasons for it's removal:

1. Being buried behind the shower when it fails I'll find out the news when the basement floods.
2. Removes two PEX lines (one run) running into the basement that catch totes and others items stored in the basement.

Once I have heard from the experts I'll draw up my plumbing layout and start cutting tubing.

Thanks

 

[rxbristol]

It's a safety device and required by plumbing code to prevent any type of sewage from entering your fresh water line. Take it from me, having had an intestinal parasite that almost killed me by stripping my intestinal lining away, you want to avoid raw sewage cross contamination. Replace the back-flow prevention valve with the Watts LF228A. You'll have to get some additional fittings from Lowes...nice valve that won't leak.

 

[danemayer]

At the Goshen rally, one of the presenters discussed the black tank flush vacuum breaker device. If I remember correctly, he said that a tech would lose his certification if he worked on the plumbing and left the vacuum breaker out. I think he even went so far as to say he wouldn't work on a coach that didn't have one.

 

[wdk450]

After having my plastic atmospheric breaker valve blow out and take out my expensive power converter from water damage, I didn't want to replace it with another plastic valve. With no metal option that I could find on the internet, I pulled out the PEX tubing from below in the crawl space, having to work 2 hours with a drill and wood chisel to enlarge the tubing hole through the subfloor above. I replaced the atmospheric breaker valve with a brass Sharkbite brand check valve and put the tubing/valve back into its position behind the toilet wall.
I would like to add that i have seen add-on tank washer systems at the local trailer supply store. These add-on systems do not have an atmospheric breaker valve. I don't know how they can sell these if this is illegal. To my mind, there is an air gap in the black tank between the sprayer nozzle and any other surfaces, and there is a check valve in the water supply line to the sprayer. How could bacteria get through both of these obstacles?

http://www.campingworld.com/shopping/item/tornado-permanent-tank-rinser-with-remote-connection/28091
(I wonder if Camping World would install this, like most of their accessories?)

 

[danemayer]

Bill,

I don't think it's illegal. But it apparently doesn't comply with RVIA Code. Can you install things to your rig that are potential hazards? Sure. Will CW help you by installing one? Who knows.

 

[porthole]

Vacuum breaker and check valve are two different items.
Because the trailers come equipped with a AVB valve high up in the wall there is no check valve at the water inlet, and the reason why you get a shoe full of water if you are not paying attention when you remove the black tank flush.

The AVB prevents any effluent from siphoning back out of the tank through the flush line.

IF your tank was near full and IF you were flushing it and IF you removed the inlet water supply there would be good chance you would siphon the contents out of that tank to the sprayer level, through the flush line.

 

[wdk450]

Vacuum breaker and check valve are two different items.
Because the trailers come equipped with a AVB valve high up in the wall there is no check valve at the water inlet, and the reason why you get a shoe full of water if you are not paying attention when you remove the black tank flush.

The AVB prevents any effluent from siphoning back out of the tank through the flush line.

IF your tank was near full and IF you were flushing it and IF you removed the inlet water supply there would be good chance you would siphon the contents out of that tank to the sprayer level, through the flush line.

I don't get any reverse water flow at the tank washer water inlet when I remove the water hose. Maybe my check valve is preventing the "shoe full of water".
When I was on the road in Yellowstone, 1200 miles away from home where I fixed this, I didn't have access to a B&B molders plastic valve, but the local Ace hardware store in West Yellowstone Montana did have the Sharkbite PEX check valve.

I am pretty sure the add-on kits DO have a check valve.

 

[Speedy]

Understanding it is code 36" above the nozzle fitting I would think a check valve (as Bill has suggested and used) would work but if the check valve failed there would be the possibility of sewage finding it's way to fresh water hookup. I'm going to ponder this a while using all of your suggestions and comments. I do like the Watts version of the valve and since I ordering my water manifold and PEX supplies from that vendor I may just replace the valve with a higher quality one and improve the tube routing.

Thanks for the help.

 

[wdk450]

Speedy:
I remember from a thread this year that there is now a BRASS atmospheric breaker valve available. That would be the best replacement, safety and functionally wise. Check out this thread: //heartlandowners.org/showthread.php/53435-Atmospheric-pressure-relief-valve