Black Water Flush Valve - Water Leaking Under Nautilus System

[ncitro]

I recently bought a quality brass Watts valve to replace ours on the black flush sometime and was disappointed on getting it home to see that warning in its box.

The warning made me think about routing the black flush line and vacuum break valve elsewhere where water leaking from the valve won't be hidden and damage things. It's currently between the shower wall and the pantry wall, like many of them.

However it should be higher than the toilet in the trailer, not just higher than the black tank, right? Even though the black flush is a system unto itself, not connected to any other plumbing, it is connected to the black tank and therefore its breaker valve must be higher than anything that feeds into the black tank.

Do I have that right Rob? Because if I do that limits the options for re-routing the black flush system to put the vacuum breaker valve in a more-accessible and less risky (valve leaks) place in the trailer.

Thanks.

I am by no means an expert, but I thought it just had to be higher than the city water connection.

There is a vacuum breaker in the toilet as well to protect the water line feeding the toilet, that one needs to be higher than the toilet (and is in the little hump on the back behind the seat).

[howson]

Do I have that right Rob?.

Mark -- Rob, Cate&Rob, documented quite a bit on this topic in this thread: https://gdrvowners.com/forum/operati...ack-tank-flush

Edit: You even posted in the thread! (It's over a year ago so understand how easy it is to forget previous conversations.)

[Country Campers]

boyscout

The vacuum breaker is suppose to be above the toilet. If there ever is a back up in the tank the nasties are suppose to come out of the toilet and not out past the valve and then on to other places. The toilet should hold back any mess from a back up but if the black tank flush is left on and the tank can be filled with pressure then get ready for a mess.

Brian

[Cate&Rob]

The RIVA rule is that the vacuum break must be above the rim of the toilet bowl (same as the vacuum break on the back of the toilet), but this seems to "assume" a residential toilet that does not have a sealed ball valve and can back up until it overflows the bowl rim. An RV toilet is sealed against backup and this seems to me to be yet another example of where RIVA applies residential rules without really considering how RVs are built. A few years back, I attempted to challenge this with Grand Design, but they were not inclined to question RVIA on this.

If the flush were left filling into a closed black tank, it would not overflow the toilet bowl (unless the pedal were pushed to open the ball valve). What would happen is that it would back up the vent stack until it reached the point where the vent pipes from the grey tanks are connected, then it would fill the grey tanks (assuming closed gate valves) until these backed up into their sinks. There are reports of filling to the vent stack on the roof, but this would only happen if there were no grey tank and sink connected to the same vent stack.

The Reflection 303RLS installation places the vacuum break (which can release water, as discussed) directly over the furnace . . . particularly its control board. My vacuum break is no longer over my furnace . . . it is also not above the toilet bowl rim, so technically does not meet "RVIA requirements".

Rob

Edit: I just realized that we went through all of this in even greater detail in the thread that Howard linked . . . I should have read that first .

[boyscout]

Mark -- Rob, Cate&Rob, documented quite a bit on this topic in this thread: https://gdrvowners.com/forum/operati...ack-tank-flush

Edit: You even posted in the thread! (It's over a year ago so understand how easy it is to forget previous conversations.)

Thanks Howard. I'd forgotten about that thread but in it my question about other options didn't get a response. With advice from Country Campers and Cate&Rob here plus re-reading that older thread I guess I've got the answer I need: the breaker valve should remain at least as high as it is. In the other thread Rob makes the reasonable argument that it should be 6" higher than the kitchen sink - ours is that already.

Obviously, moving it somewhere more accessible and visible in the basement is not a good idea. I guess I'll get another water alarm to place under the original / current location of our breaker valve, and replace the valve with the good one I bought, so one less thing to worry about.

[Andy+Mo]

The new (OEM) valve arrived today and I installed it in just a few minutes. Ran some water through the system and no leak. I tested the old one once i pulled it off by just blowing some air through and sure enough it doesn't seal. Problem fixed. Thanks for all the insight and guidance.

[Canyonlight]

The new (OEM) valve arrived today and I installed it in just a few minutes. Ran some water through the system and no leak. I tested the old one once i pulled it off by just blowing some air through and sure enough it doesn't seal. Problem fixed. Thanks for all the insight and guidance.

Andy - good to hear !

Dan