Black tank sprayer plugged

Most likely, the backflow preventer at the inlet is fouled up. Sometimes you can hit it with your finger, just be ready for a water to come back at you.

agree with the back flow valve and it shouldn't be hard to get to. The line should go up to the valve and then back down to the tank.

Look under bathroom sink. The backflow preventer is usually way up behind the plumbing for the bathroom sink.

therink wrote:
Look under bathroom sink. The backflow preventer is usually way up behind the plumbing for the bathroom sink.

The above is a drain vent.

There is probably a check valve where the hose attaches to the trailer that is stuck. A vacuum break is usually installed inside the trailer near the point of entry, but that is unlikely the cause of no water flow.

Lynnmor wrote:

therink wrote:
Look under bathroom sink. The backflow preventer is usually way up behind the plumbing for the bathroom sink.

The above is a drain vent.

There is probably a check valve where the hose attaches to the trailer that is stuck. A vacuum break is usually installed inside the trailer near the point of entry, but that is unlikely the cause of no water flow.

Exactly.

Lynnmor wrote:

therink wrote:
Look under bathroom sink. The backflow preventer is usually way up behind the plumbing for the bathroom sink.

The above is a drain vent.

There is probably a check valve where the hose attaches to the trailer that is stuck. A vacuum break is usually installed inside the trailer near the point of entry, but that is unlikely the cause of no water flow.

Not true, the black tank flush has a backflow preventer between the outside flush connection and the black tank. It has nothing to do with a vacuum breaker (found on the vents of some gray water tanks).

My Outback quit working one day out of the blue. I could hear the water pressure getting to the tank and then nothing. I pulled down enough underbelly to see where the sprayer was and ended up cutting a 3 sided trap door under the sprayer for access. When I pulled it out the sprayer was clogged with sand and assorted "organics". I cleaned it out and drilled the holes about .020 bigger. I resealed the trap door with gorilla tape. It's be fine since.

See if this helps:

Flusher

Thanks for all the tips..I did not know there was a backflow preventer installed..I had thought something had plugged at the end of the line so I tried a piece of flexible wire..it went in about 5" or so and stopped..How or what do I do to fix the backflow preventer?

ashnic wrote:
Thanks for all the tips..I did not know there was a backflow preventer installed..I had thought something had plugged at the end of the line so I tried a piece of flexible wire..it went in about 5" or so and stopped..How or what do I do to fix the backflow preventer?

LYNMORE posted a link of the parts and installation of a black tank flush system. My system similiar layout. You might have to take some access panels off to find the atmospheric vacuum breaker/check valve and unscrew the plumbing tubing and remove/replace or repair (this is where my system had stink bugs jammed up inside the rectangular area..cleaned out debris and reinstalled..works fine now). If your referring to the water inlet check valve you can remove mesh screen inside the outside hose connector and try clean flush out the valve/spring?..if its like the one found on the city water hookup on your rv. I had to replace the city water inlet connection as it could not be fixed on my unit. Not sure though if the black flush inlet same design/function as the city water inlet. Hope that helps..and hope you dont have to crawl and stretch as much as my friend and I had to fix mine..