Underneath bathroom sink

[Ranchhand]

What is this black piece with the two white pex pipe hooked to it. Been using the camper for three weeks now with no water problems. Went to flush black tanks today and the black thing was leaking water out of the top of it I think. Turn black tank flush off and water quits leaking. Any help would be appreciated. It’s a 2019 cougar 369BHS by the way.

Thanks

[ChuckS]

This is the cheap OEM anti siphon valve that is junk and has been for may years .. it has caused more folks floods and heartache...

Remove the valve and either replace with a brass one from home depot or lowes or remove and splice lines together with a Shark Bite union and be done with the trouble forever...

[Ranchhand]

Ok thanks. Is it supposed to have water pressure against it when rinsing the black tank

[Javi]

Originally Posted by Ranchhand

What is this black piece with the two white pex pipe hooked to it. Been using the camper for three weeks now with no water problems. Went to flush black tanks today and the black thing was leaking water out of the top of it I think. Turn black tank flush off and water quits leaking. Any help would be appreciated. It’s a 2019 cougar 369BHS by the way.

Thanks

It is a cheap piece of junk that every trailer owner will have to replace.

It is an anti-siphon valve, its purpose is to prevent water from the black tank being sucked into the camp water system when you use the flush system.

The simple solution is to replace it with two 90` elbows and a short piece of PEX and a hose bib anti-siphon valve on the water hose.. the complicated solution is to buy a brass anti-siphon replace and wait for it to also leak..

https://www.amazon.com/Eastman-20199...79539603&psc=1

[Ranchhand]

If I’m going to just take it out and hook the two lines together is there any reason why I can’t make the lines shorter so it’s easier to put it back together instead of being right underneath the bottom of the sink. I assume that it is 1/2 inch PEX or is it 3/8.

[chuckster57]

It’s 1/2” pex. Just make sure you use an anti siphon valve somewhere.

[Javi]

Originally Posted by Ranchhand

If I’m going to just take it out and hook the two lines together is there any reason why I can’t make the lines shorter so it’s easier to put it back together instead of being right underneath the bottom of the sink. I assume that it is 1/2 inch PEX or is it 3/8.

It is 1/2" PEX. The way I do it is to pre-make the fitting with 3"-4" of PEX with a 90 on either end then pull one line down where I can get to it and clamp it then pull the other down to get it clamped.

You should leave it as long as possible because it is more difficult for any suction to get started. Technically I think it is supposed to be at least 16" above the tank. But I just cut the PEX just below the OEM clamps and go with it.

[Ranchhand]

Originally Posted by chuckster57

It’s 1/2” pex. Just make sure you use an anti siphon valve somewhere.

Where would you suggest to put one if I remove from below the sink

[Javi]

Originally Posted by Ranchhand

Where would you suggest to put one if I remove from below the sink

Screw the one I posted onto the water hose, mine just stays on the flush hose, that way I can't forget to use it.

[Ranchhand]

Thanks everyone I fixed with a couple of shark bite elbows and a short piece of PEX

[Javi]

Originally Posted by Ranchhand

Thanks everyone I fixed with a couple of shark bite elbows and a short piece of PEX

You might want to invest in a PEX clamp tool, these RV'S are always needing something fixed and sharable fittings are expensive compared to clamps.

[ChuckS]

Smart choice on taking the valve out completely.. many folks forget to blow that line out with air when winterizing and if water is in the valve it freezes and cracks.. furs time it gets used next season the OP has flood in the bathroom..

Personally I don't use the stupid thing.. I reverse flush my tanks thru sewer line and it cleans all the tanks.. not just the black..

There are nay Sayers that say it don't work... but it does.. has for the last several decades for my tanks in several different RVs

[Sonders]

Personally I don't use the stupid thing.. I reverse flush my tanks thru sewer line and it cleans all the tanks.. not just the black..

sorry to thread jack but Chuck, what do you mean by this? I'm interested to know what this procedure is as my black tank flush hasn't worked since we bought our camper. I have a thread going for the issues I'm having with the black tank flush system as well, but haven't had any more activity in the thread. Chuck you can PM it to me if that would to keep this thread on topic. Thanks.

[jxnbbl]

Quick question on this check valve. The tank flush in my bullet has never worked. I assume I just hook a hose up to the 'flush connector' and add water pressure. The pressure just builds and no water flows. I think this check valve just cuts off the flow. (It does not leak under the sink in my case).


If I just add an anti-siphon device to the connector and replumb this do you believe that the tank flush would actually work?


thanks

[Javi]

This is my solution 👌

[sourdough]

Solve it like Javi shows. Get a anti siphon (brass) valve to screw on the end of the hose and into the inlet on the trailer and go to flushing.

[Skippy38]

Here is my solution below. By the way, I got called everything from a murderer to a genius by the "know it alls" on youtube. Some said I was going to backflow and kill everyone in the campground lol. I do have my black tank flush hose protected by a brass 1 way valve like Javi shows above at the source so it cannot backflow. This is very easy to do and will eliminate lots of headaches and floods in your bathroom. Mine works perfectly now...

https://www.youtube.com/watch?v=urywWdM6TrA

[B-O-B'03]

Originally Posted by jxnbbl

Quick question on this check valve. The tank flush in my bullet has never worked. I assume I just hook a hose up to the 'flush connector' and add water pressure. The pressure just builds and no water flows. I think this check valve just cuts off the flow. (It does not leak under the sink in my case)...

There have been many folks reporting their check valves were installed backwards, yours might be too. I believe the valve has an arrow on it, indicating flow direction.

-Brian

[CedarCreekWoody]

Just to clarify that is an anti-syphon valve, not a check valve. Wouldn't want you to order the wrong thing.

[jxnbbl]

So it didn't work ( I created one that I could screw on/detach) instead of the putting the trailer in storage on our return going back to the dealer to deal with it. I'm betting that it was never hooked up at the tank and has a plug in it.