Kitchen plumbing I'm having a plumbing problem with my 2014 Pheaton LH. There is a 2"

[Redbear7938]

I'm the new owner of a 2014 Phaeton 42LH. I believe the plumbing in the kitchen sink is wrong as there are no water traps under either sink. The two drains join together in the middle and then there's a vent pipe about a 2 inch pipe that goes up at a 45° angle towards the back of the cabinet. This pipe is wide open at the end. When I drain the sink the water comes gushing out this pipe.

1.). Should there be water traps under the sinks in the kitchen?

2.). Do I need to call an RV service company to fix this work in a regular plumber do the job?

3.). As I'm new to the RV world, is it possible that this is plumbed correctly and
the water is just supposed to flow out underneath that vent pipe?

Thanks for your help!

[davidc70]

Usually there is this on the end of the vent which allows air in but no water out.

Sure-Vent 1-1/2 in. x 2 in. PVC Air Admittance Valve-39016 - The Home Depot


Dave

[luvlabs]

You have a Hepvo waterless trap under the sink and the uncapped pipe might be the air admittance vent to the tanks (all waste plumbing is vented, just like your house plumbing). Replace the AAV valve (as the previous poster suggested) and all should be fine.

On your waterless trap - if you need to clean it, do not run mechanical things through it as they will damage it. You can use Liquid Plumber and the like to clean it.

[select55]

Originally Posted by Redbear7938

I'm the new owner of a 2014 Phaeton 42LH. I believe the plumbing in the kitchen sink is wrong as there are no water traps under either sink. The two drains join together in the middle and then there's a vent pipe about a 2 inch pipe that goes up at a 45° angle towards the back of the cabinet. This pipe is wide open at the end. When I drain the sink the water comes gushing out this pipe.

1.). Should there be water traps under the sinks in the kitchen?

2.). Do I need to call an RV service company to fix this work in a regular plumber do the job?

3.). As I'm new to the RV world, is it possible that this is plumbed correctly and
the water is just supposed to flow out underneath that vent pipe?

Thanks for your help!

like the picture above theres supposed to be a one way vent valve on the open pipe and that pipe should be level or above the bottom of the sink

[96 Wideglide]

They all have air admitance valves, but that alone doesn't replace a 'P' trap.
I've never seen a sink without a 'P' trap .

[select55]

Originally Posted by 96 Wideglide

They all have air admitance valves, but that alone doesn't replace a 'P' trap.
I've never seen a sink without a 'P' trap .

funny I was thinking the same thing but based on his post its obvious it came from factory without one BUT the open pipe hes talking about also obviously has the admittance valve missing in action

[luvlabs]

Tiffin uses Hepvo waterless traps for a number of sinks in a coach. Look them up, they are the same as a P-trap, they just don't need water to function.

[select55]

Originally Posted by luvlabs

Tiffin uses Hepvo waterless traps for a number of sinks in a coach. Look them up, they are the same as a P-trap, they just don't need water to function.

that will certainly explain the fact of no regular gooseneck for sure but not the major water leaks hes taking about

[Redbear7938]

Thanks for the good info. I'll get the AAV referenced above and see if that solves it. Shakedown cruise continues.

[96 Wideglide]

Originally Posted by select55

that will certainly explain the fact of no regular gooseneck for sure but not the major water leaks hes taking about

I agree.
I don't think the AAV is there to stop grey water. When your sink is draining, the AAV opens up to allow air in. If they missed installing a AAV on the OP's plumbing, it cant get any more open than that!

[Dtwallace]

Originally Posted by 96 Wideglide

I agree.
I don't think the AAV is there to stop grey water. When your sink is draining, the AAV opens up to allow air in. If they missed installing a AAV on the OP's plumbing, it cant get any more open than that!

I think you are missing the point.

The OP's drain water is taking the alternate path of least resistance as its rushing out of the sinks, and that's the open vent line.

A one way valve at the end of the pipe as mentioned should resolve the over flow issues by stopping water flow out, but letting air flow as needed in.



Merry Christmas to all

DTW

[96 Wideglide]

Well, I don't have the Hepvo waterless drains in my coach, but, I'm sure I could remove the AAV and drain the sink, without water gushing out of the pipe that the AAV screws onto.

[Old-Biscuit]

Originally Posted by 96 Wideglide

Well, I don't have the Hepvo waterless drains in my coach, but, I'm sure I could remove the AAV and drain the sink, without water gushing out of the pipe that the AAV screws onto.

The AAV closes when there is 'positive' pressure in drain line and opens when 'negative pressure' is present

Remove your AAV, fill sink and then drain sink.......
Weight/volume of water running down drain line would cause positive pressure until it slows down and THEN AAV would open allowing air in drain line.
W/O AAV that full sink WILL gush out open stub pipe for a little while

So go ahead and try it.....then after cleaning up post how much water did come out of stub pipe where AAV should have been


AAVs OPEN almost immediately when draining grey tank so 'p' traps do not get sucked dry.

[96 Wideglide]

Can't test it, my coach is currently winterized with antifreeze.

When you dump your grey tank, air from the roof vent displace the grey water.