Black Water Tank Cleaning line plumbing

[Gary Short]

I have a 293RK with an issue with the city water hookup and plumbing as regards the black water tank cleaner I tried to rinse out the black tank yesterday and flooded the unit. Does anyone know how the plumbing lines run from the exterior hose bib into the tank sprinkler. it seems to run in and up behind the sink and somehow it is rerouted back to the black tank. Any help out there?

[chuckster57]

You pretty much have the idea. It goes from the bib at the exterior wall to an anti siphon valve and then to the black tank.

It's not uncommon for the anti siphon valve to stick and when you turn on the water it's like a sprinkler head.

Cheap part and in my opinion that's the biggest problem with those. I've lost count of how many I have replaced on NEW units prior to delivery to retail customer.

[JRTJH]

The black tank flush connection on the outside of your RV runs to the black anti-siphon valve located under your bathroom sink, and from there down to the black tank where it's connected to the black tank spray assembly.

Here's a picture of the anti-siphon valve under the sink: The blue hose comes from the outside connection and the white hose goes to the tank sprayer... There is nothing (except a possible elbow connection) between the hose bib connector and the tank spray head except that pipe and the anti-siphon valve.

[Gary Short]

does the anti ayphon valve just screw to the underide of the sink counter. I don't have a lot of room to work in the small vanity cabinet, and would hate to have to remove the sink to gain access.

[JRTJH]

No the anti-siphon valve sits freely on the two hose connections. It is very lightweight and doesn't need any support.