Community Forums

USMCRET · 07-30-2015, 03:55 AM

I've been getting a healthy stream of water pouring out from the black tank flush inlet when disconnecting the hose. It appeared to me that the backflow check valve was malfunctioning.

Upon disassembly, it does not appear as though there is a check valve in the water inlet. That doesn't sound right. I also disassembled the fresh water inlet and it has an obvious check valve. I could swear that I did not have this back flow issue in the past.

I bought new inlets for both, but am wondering if the tank flush is supposed to have a check valve. I know I'm getting old, but am I also going nuts? (maybe that's for a different thread).

cc8375 · 07-30-2015, 05:25 AM

My line runs from the left side of the coach to the right. When disconnecting the water in that line runs back. My check valve is at the tank, not in the line. When captured once, it was about 3 ounces of water.

millerj · 07-30-2015, 06:47 AM

I had my coach at Newmar a few weeks ago because my black flush would not work. I thought I had the opposite problem as you in thinking my back flow preventer was somehow closed and wouldn't open. The first thing Newmar did was connect a compressed air line to the system then they connected a water hose to the inlet and everything worked ok. The Service Tech thought the sprinkler openings may have been plugged. On my coach he told me the back flow preventer was up under the sink next to the shower. I would have never looked there for it.

tom chelbana · 07-30-2015, 08:49 AM

Put a shut off valve on black water tank flush and should take care of problem.

GaryKD · 07-30-2015, 09:57 AM

Hi USMCRET,
We have the same coach. I get very little water when disconnecting the water supply from the black tank rinse. I can't help locate where the back flow valve is located. On this line, I've never looked for it.

dsbear · 07-30-2015, 10:03 AM

I don't have a Newmar, but on my Thor the anti-syphon air gap is under the bathroom sink and when I disconnect all of the water in the line from the air gap to the connection point runs out. This is expected if the air gap is functioning properly.

David, Heidi, M and Moose(the lab)
2011 Damon Astoria
Pulling an'09 Chevy CrewCab.

andyh · 07-30-2015, 07:49 PM

It is normal to have the line empty out when when the hose is disconnected. It is the water between the inlet and the vacuum breaker (anti siphon valve) which is located somewhere inside the coach, above the floor.