Secret to blank tank flush?

[nomad297]

Originally Posted by bob caldwell

As I have a factory valve in my hand, the drawing is correct. the problem I see in post 37 is the valve lay'n on it's side.....the rectangular top cover should be at the top as there's a flapper disc in there that floats under it's own weight and with valve lay'n on it's side the flapper can't close.

Bob, he took the picture while laying on his back pointing the camera at the bottom of his counter. So the pair of red and blue waterlines are actually coming through the side of the cabinet and the vacuum breaker is oriented properly in the vertical position.

Bruce

[bob caldwell]

Ahhhhhh

[Forester Fred]

Bob, I was laying on my back when I took the photo. The flat part of the valve is up against the bottom of the vanity top.

[OldCoot]

I would still remove the factory junk and install a quality brass backflow preventer at the back of the inlet and connect it directly to the black tank flusher. JMO.

[itat]

Did FR always install a backflow preventer with the black tank flusher inlet? Today I opened up the cabinet to see the back side of my inlet and there is just a 90deg elbow. No backflow preventer. Maybe the previous owner removed it?

Sorry pic shows up sideways.

[youroo]

Yep to Post# 45. Youroo!!

[itat]

Anybody have a picture of a Watts No. 7 installed?

[bob caldwell]

Pour'n rain here, but even if it wasn't, not a pic person....sorry.

[Forester Fred]

So, this gets curiouser and curiouser......

I took my rig to the dealer this morning to have them take a look at the black tank flush as well as a couple other minor problems.

The technician was able to duplicate my "sprayed water all over under the bathroom cabinet" issue. He ended up taking everything apart and found debris blocking the line leading from the backflow preventer/vacuum breaker to the black tank. He also had to take off the inlet from the outside of the coach and found debris blocking the screen on the inside of the inlet. He asked me if I let the black tank get too full. No - never more than 2/3rds. And, if it was too full, the toilet is lower than the valve so wouldn't I have had backup there? To which he responded that sometimes debris works it's way in there at the factory.

He cleaned everything up, tested it and repositioned the valve so it's easier to get to (same height).

If the black tank was overfull, wouldn't I have seen it when flushing the toilet? And, I could see maybe debris backing up into the line downstream of the antibackflow valve, but not all the way past the valve up to the inlet filter screen.

Any thoughts?

[VinceU]

Originally Posted by Forester Fred

So, this gets curiouser and curiouser......

I took my rig to the dealer this morning to have them take a look at the black tank flush as well as a couple other minor problems.

The technician was able to duplicate my "sprayed water all over under the bathroom cabinet" issue. He ended up taking everything apart and found debris blocking the line leading from the backflow preventer/vacuum breaker to the black tank. He also had to take off the inlet from the outside of the coach and found debris blocking the screen on the inside of the inlet. He asked me if I let the black tank get too full. No - never more than 2/3rds. And, if it was too full, the toilet is lower than the valve so wouldn't I have had backup there? To which he responded that sometimes debris works it's way in there at the factory.

He cleaned everything up, tested it and repositioned the valve so it's easier to get to (same height).

If the black tank was overfull, wouldn't I have seen it when flushing the toilet? And, I could see maybe debris backing up into the line downstream of the antibackflow valve, but not all the way past the valve up to the inlet filter screen.

Any thoughts?

Probably referring to shaving debris from original fabrication. The fine plastic trash plugs toilet flush inlet, faucets, showers etc. yours found its way to the black inlet. Definitely not from the tank overflow, that's enough head to cause quite a calamity.




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[Forester Fred]

I think what I'm going to do at this point after reading all the horror stories related to the high cost black plastic valve that apparently the bulk of RV manufacturers install, is take it out and get a real one. I'm going to take the valve to a local plumbing supply house, let them see the fine piece of American plastic craftsmanship and see what they can come up with for a backflow preventer and vacuum breaker. I know other members have installed Watts #7 backflow preventers and that may be what I end up with, but I would like to try to keep the vacuum breaker involved in the system. I figure someone who designs these systems knows more than me and there's a reason why there is a backflow preventer and vacuum breaker there.

I did notice when I took it out that the vacuum breaker is pretty much a joke. It's a piece of white plastic that moves up and down inside the cylinder of the valve body. As soon as it gets some use it's going to wear and that's where the leaks are probably coming from that a lot of people are complaining about.