Leak at Connection for Black tank flush

[Waterboy909]

at the point of connection with my hose and the black tank flush the value leaks . I've tried tightening the connection with a plumbers wrench without torquing to hard and still the same leak.

I've read a bit and it seems that the backflow prevention device could be the issue. I have easy access to mine, I believe its a black box with two tubes connected to it under the sink.

What I haven't been able to find is how to troubleshoot this issue. Any tips? do I just take the box off and turn it around?

Sorry for maybe a repeat question, I did my best to find a thread before asking but turn up empty.

Thanks in Advanced

[chuckster57]

If the anti siphon valve is leaking, the only repair is to replace it. You can get another cheesy plastic one or upgrade at your local hardware store. both fitting are 1/2" NPT. You can't just turn it around as the valve is one way.

[Waterboy909]

Sorry to clarify its not the siphon valve that leaks. It's the connection at the port in the hook up bay. The leak happens between the exterior hose and the valve that you screw the hose into

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[chuckster57]

Make sure the washer is there. You can use any hose washer, I use the screen style like on the city water connection.

[SteveC7010]

Sorry to clarify its not the siphon valve that leaks. It's the connection at the port in the hook up bay. The leak happens between the exterior hose and the valve that you screw the hose into

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OK, so it is a simple garden hose connection. If the leak is between the male and female connectors, it is identical to any garden hose hook up at your home. What would you do if you had a similar leak on the hose in your yard?

Well, the washer is first and obvious thing to check. If it's not doing its job, replace it. And let's be real here, this is not an RV problem or RV parts. You can use the same washers you buy at the local hardware store for your home garden hose.

If the washer is not the problem, then exactly where is the leak coming from? The female end on the trailer side is many times a single assembly that includes a check valve. On my Cougar, it's all plastic, and it is very possible that the plastic housing could crack and leak when pressure is applied. If you need to replace that assembly, that may require a trip to the RV parts counter. But, it is an easy replacement, at least on my Cougar. A couple of screws and a worm clamp.

If the leak is being caused by a deformed or damaged end on the hose, cut it off, get a replacement at the hardware store, brass or plastic is your choice, and install the new fitting.

[SkiSmuggs]

Mine is leaking there also and know it is not a washer as I have never removed the hose. My bigger problem is the check valve under the sink as it now leaks whenever there is water pressure. Ordered a replacement from Walmart.
Back to the OP. It seems like the handle assembly for the tank washer leaks whenever it is turned on. I don't know how to get it out, but assume that it is easier to replace than to repair.

[Waterboy909]

Hmm thanks for the insights, I'll try the washer see if that helps. I had heard that this can occur when the backflow preventer is installed incorrectly. Does anybody know how to tell if it is the problem?

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[chuckster57]

Hook up the water and turn it on. Then watch the tank gauges. If you can get to the valve, you can sometimes hear the water flowing.

It will only flow if the valve is installed correctly.

[ctbruce]

Mine drips too. Since it is only for a short while during dumping, I just don't put much emphasis on it. When I stop rinsing, it stops leaking. Close enough for government work.

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