Leak behind shower

[oldSalt]

Have had a minor intermittent leak and finally managed to trace it through the pantry access to the back of the shower. The cold and hot water lines and connections are okay; it's the 2 white pex lines with a black plastic thingamagig connecting them. The leak is coming from where the black thing attaches to the 90 degree fitting. It's a screw fitting and is leaking through the threads. I wrapped teflon tape around the threads and made sure all the fittings (2 screw clamps holding the 90 degree adapters and both plastic hand tighteners gthat come off the black plastic thing and attach to the 90 degree adapters), all to no avail. It leaks with the water turned off and on, but not when I shut it off at the city water pedestal. I have my pressure regulator set at 50 psi, so I'm sure it isn't due to high pressure.
It's not a major leak (maybe a pint a day), but it sure is irritating. Thanks in advance for any help.

Jim

2006 36TK3

[ponch]

First off do you happen to have a hose line connected thru a "T"
to the washer for your black water tank?

That black fitting is the safety valve between the black water and fresh water tank.

Let me know.

Ponch

[bstark]

You have a leak at the black tank flush anti-syphon device. Unless your black tank flush is hooked up permanently to some water source and the shut-off device is leaking there should be no leak at that point as there shouldn't be any residual water pressure there. When you detach/shut-off water supply to the black tank flush, the absence of pressure from the supply side allows a small "poppet" type valve to open which allows air into the system at that "high point" which in turn allows water to drain backward to the flush hook-up which breaks the water column and prevents water being syphoned out of the black tank all the way back to the flush port. there have been cases of the preventer being installed backwards but that would simply not allow water past the preventer to the flush nozzle & into the black tank.

[Motor31]

Our rig had the anti siphon valve leak as well. It leaked twice, the first being because it never had the connections tightened at the factory. They were both loose and held on by just a couple threads. The second time it had just failed. They are fairly common at a well stocked RV supply house or dealer. I found the replacement on the shelf at a fair sized other brand dealer in Louisiana.

One thing to do is to make sure you do not have a water source hooked up to the black tank flush all of the time. If the water source valve is leaky and allows water to flow, even slowly, it can get up to the valve and a low pressure water flow seems more prone to leak than a full or moderate pressure flow when flushing. It also tends to fill up the black tank faster as well.

[oldSalt]

First off--thanks for all the replies.

No, I do not keep a line connected to the black tank flush inlet. I empty my black tank every 2 weeks and flush it at that time, then disconnect my hose.

Sounds like I'm going to have to make a trip to a local rv dealer for a new valve.

Thanks again, guys.

Jim

[Suitedreams]

We have a 36SB and ours has leaked twice. First time, I tightened the two white fittings and it lasted about two months. The second time, I pulled the fittings apart and went to Lowes and got some new washers, so far, no problems.

[mloftin]

Well this seams to be an on going problem, I was flushing the tank on Sunday and noticed I had a water leak in the basement after doing some research found that it was the water line going to the vacuum breaker for the flush only finger tight. Right now I am not impressed with QC at Double Tree to mant things that should be caught before it leaves the factory..

[weekenderdude]

My local RV parts place didn't carry these valves. Call Dave in parts at Doubletree and he will mail one to you very inexpensively.

They are called anti-syphon valves. The failure rate is pretty high.

[Motor31]

If you do find an anti siphon valve at a parts location they are not expensive. Keeping a spare is not a bad idea particularly if you are in an area with very hard water. The calcium build up will eventually clog the sliding valve in it.

[weekenderdude]

Just got the new value on the mail. They sent it to me UPS 2nd day air. The shipping was probably more expensive than the part.

My original value was black and the new one is clear. Let's hope this one holds up.