Black tank flush anti siphon valve

[chuckster57]

Originally Posted by Spletbr

Pardon me but what does this valve do and why should I be concerned? I like to be proactive when I can!

The anti siphon valve is there to prevent any contaminated water from getting into the fresh water supply. As a rule in RV’s the valve is installed at a higher point than the inlet and spray port on the tank and since science has shown water doesn’t travel “uphill” it’s kind of an “insurance” fitting.

IF the fresh water system were to suddenly have a catastrophic failure it could potentially “pull water” from the flush system.

[bobbecky]

The valve needs to be installed at least 6" higher than the rim of the toilet to work properly. https://www.recpro.com/rv-vacuum-bre...571-vac-chk-a/

[Gregory]

Thanks to the chuckster I did the by pass behind shower faucet and am on to my next adventure. It’s just like a house but they have wheels. Happy and safe travels

[Arnold12519]

I have an Alpine. I removed mine completely. Easy fix.

[terrythetech]

IMHO It's to prevent black water tank sewage from back-flowing out the tank flush connection which is most likely to prevent any possibility of contamination to the freshwater outside water system. It is highly unlikely to ever happen but I suppose its a requirement by law. I have had to remember to blow out the water in that valve before winterizing every year or the plastic 1-way valve will freeze and break (again). I will be completely removing it this spring when I open up the camper this spring. It is just 1 more thing to worry about if it will leak or not the 1st time I use it. If you are moving the camper a lot, I would just put a cap on the hose connector to prevent anything from coming back out of the connector. It will be eliminated 1st chance I get. Mine is under the vanity and I don't want to find out it leaked into the bathroom after I flush the tank.

[sourdough]

Originally Posted by terrythetech

IMHO It's to prevent black water tank sewage from back-flowing out the tank flush connection which is most likely to prevent any possibility of contamination to the freshwater outside water system. It is highly unlikely to ever happen but I suppose its a requirement by law. I have had to remember to blow out the water in that valve before winterizing every year or the plastic 1-way valve will freeze and break (again). I will be completely removing it this spring when I open up the camper this spring. It is just 1 more thing to worry about if it will leak or not the 1st time I use it. If you are moving the camper a lot, I would just put a cap on the hose connector to prevent anything from coming back out of the connector. It will be eliminated 1st chance I get. Mine is under the vanity and I don't want to find out it leaked into the bathroom after I flush the tank.

Terry when I took this one out I just put on 2 90 degree shark bite fittings and a small length of pex where the valve was cut out. You really shouldn't have to cap the connector as nothing is going to come back out of that line unless there is some sort of suction pulling the black tank contents out AND the lines to the anti siphon loop are left extended up under the cabinet and not cut off short.

[Javi]

Originally Posted by terrythetech

IMHO It's to prevent black water tank sewage from back-flowing out the tank flush connection which is most likely to prevent any possibility of contamination to the freshwater outside water system. It is highly unlikely to ever happen but I suppose its a requirement by law. I have had to remember to blow out the water in that valve before winterizing every year or the plastic 1-way valve will freeze and break (again). I will be completely removing it this spring when I open up the camper this spring. It is just 1 more thing to worry about if it will leak or not the 1st time I use it. If you are moving the camper a lot, I would just put a cap on the hose connector to prevent anything from coming back out of the connector. It will be eliminated 1st chance I get. Mine is under the vanity and I don't want to find out it leaked into the bathroom after I flush the tank.

This is what most of us do.. then use one of these on the hose.. https://www.lowes.com/pd/AMERICAN-VA...E&gclsrc=aw.ds

[terrythetech]

Sounds like a (my) plan for this spring. Thanks for the tip and have a swell day!