Vacuum Breaker on Black Tank Flusher Leaks

[Bob Jae]

Last fall I noticed water leaking out of the coach after I dumped my holding tanks and used the black tank flusher.  Yesterday I found the leak.  It was the Vacuum Breaker.  Of course it is mounted way back in a corner behind the stove and blocked by a partition and brace that supports the stove.  I will attach some pictures to show where it is.

I checked on vacuum breaker installation requirements and the code says that the bottom of the breaker has to be 6 inches above the top of the tank. 

Well I have plenty of space in the tank bay so I plan to move the breaker down into that heated bay where I will be able to keep an eye on it, they seem to leak a lot, and maintain it.  I may also add a back flow valve just for added safety as I see others have done.

Posting here incase I have missed something and it needs to be mounted higher for some reason.  Now to post some pictures.

[Fred Brooks]

     Hi Bob,

     I have replaced about 15 of these over the years. Yours is probably plastic and the diaphragm inside has failed or is compromised in some way. The reason for the RVIA code is to allow enough elevation for the unit to drain in both directions once the water pressure is removed. This prevents contamination or back siphoning to the fresh water source. Darn engineers always put this stuff where-ever because they don't get to replace it. If you are going to relocate the valve, make sure it is above the waste tank and gravity will insure proper drainage.
    Also take note of the "arrow" on the valve so you know the direction of the water flow. Brass replacements can be found at any plumbing supply store or on line. Don't waste your money on a redundant back flow check valve, it just slows down the operation and duplicates what you already have.
       Regards, Fred

[Joel Ashley]

Mine's an '06 Monterey also, but the valve was put in a bit more convenient spot... under the streetside bath cabinet, just above the water bay.
-Joel

[Bob Jae]

Just an update.  I decided to keep the vacuum breaker up under the counter, that way it is above the level of the toilet.  I managed to wiggle in under the cooktop and cut the Pex lines.  Once I got the unit out and looked at it, the plastic one way valve was cracked.  So I took that out as it is redundant and not called for in the Santi-Flush install directions.  Then off to the hardware store and picked up two inline Sharkbite fittings.  Re-installed and put a clamp to the wall.  Now we should be high and dry.

[Harold and Gloria Skipworth]

Had a similar problem but with the nylon check valve.  Mine is behind the washer/dryer and jammed into a corner.  Rather than remove the washer to gain access I mixed up some epoxy and coated the crack in the valve with several layers.  so far no leaks.