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MikeandRuth · 06-01-2019, 04:42 PM

I am posting this because I decided some of you with coaches of similar age to mine might find it informative.
I flush my black tank for about 15 minutes every week after I dump it. This week when I turned the flusher on it sounded different and in about 60 seconds I had water running off of the top of my black and grey tanks. I pulled the blank panel off of the passenger side and found the tops of both tanks wet.
I have been in and out of that compartment many times but never really paid any attention to how the flusher is plumbed. The inlet tube comes over to the roof vent hole in the floor and goes up. It then comes back down an goes over to the flushing head connection on the black tank.
I removed the side wall section beside the stool that covers the vent pipe to the roof and found a check valve and an anti siphon valve connecting the up and down PEX. The anti siphon valve was worn out. The post that guides the anti siphon donut was pretty much gone. The check valve looked ok but was stuck open with what looked like a piece of calcium. I threw them both away and installed a brass 180 and put it all back together. They way I use the flusher I do not need a siphon break or a check valve. We had been experiencing some odor in the stool room and that is now gone also. I was seriously considering lifting the stool to see if I had a seal issue but now I don't need to!

Old-Biscuit · 06-01-2019, 10:50 PM

The anti-siphon vauum breaker backflow preventer device is there so waste water doesn't contaminate the potable supply water system.

Whew!
Now that I have gotten that public service announcement/warning out of the way.........

Those valves fail.and when they fail they can FLOOD an RV

You are fortunate that the water just came down into your wet bay area.
Some flood bathrooms, some flood closest cause they are installed in them, some are hidden behind shower walls and flood thru-out the area.

Removing them/replacing with hard piping/fittings does open the 'potential' for cross contamination but the 'probability' is extremely LOW
*Waste tank would have to be OVERFILLED (water going up vent line)
*Potable water supply would have to completely fail with spigot left open
*waste water would have to backflow out of waste tank thru the holes in spray nozzle up the 2' or piping then back down and out into water hose then flow thru supply spigot into potable water system
Potential...yes
Possible...yes
Probable.....yes given the perfect storm

A simple garden spigot vacuum breaker installed on end of hose between flush connection .....probability drops to almost nil

MikeandRuth · 06-02-2019, 09:02 PM

I get the back flush theory with a full tank but my potable water is totally separate from the hose I use for my flushers, which I have in both my grey and black tanks.
I also have on/off valves on both ends of the hose so it cannot be accidentally turned on by some helpful individual.
Further, it was beginning to emit an obnoxious odor and I had no idea it existed until it failed completely. I am not reinstalling one.

Old-Biscuit · 06-02-2019, 10:26 PM

Quote:

Originally Posted by MikeandRuth

I get the back flush theory with a full tank but my potable water is totally separate from the hose I use for my flushers, which I have in both my grey and black tanks.
I also have on/off valves on both ends of the hose so it cannot be accidentally turned on by some helpful individual.
Further, it was beginning to emit an obnoxious odor and I had no idea it existed until it failed completely. I am not reinstalling one.

Separate from YOUR potable water....
but the hose you use for flusher IS connected to CG potable water system.
(or do you have a some other source for that water???)