Fifth wheel sink problem

[ErsandGrrg]

Hello, all!

I have a 39 foot open road pilgrim 5th wheel. My kitchen sink does not drain properly. It does drain, really really really really really really really really really slowly, if there is too much water in the sink. If I just turn the faucet on and turn it off, the water drains fine, but if any amount of water builds up, say if I am doing the dishes, the sink takes forever to drain. The water does not even look like it is moving and there is a column of teeny tiny bubbles that come up out of the drain. Someone please help me, I am at my wits end.

I read your other post about someone who had a similar problem and I tried all of the suggested fixes, but none of them have worked. I have opened the tank, I have run hot water down it, I have taken apart the P trap and cleaned it out, and the water is still not moving. I went and checked the vent on the roof and there does not appear to be anything blocking it. If I push air down into it, as soon as I stop, I can feel the air push back and there is a gurgling sound. Someone on the other post had mentioned that severe vacuum lock could cause this problem. If that is the case, how do I fix it?

[momentum_rv]

Unless your tank vent is part of your sink plumbing that is NOT it.

The problem is there is no way for the water to go down easily if there is no way for air to get in also... hence the AAV which sounds like it is not allowing air in for some reason. It should just unscrew but may be tight from the sealant used.

If your vent to the roof is directly connected to the sink P-trap plumbing then you have a vent problem.

[ErsandGrrg]

If the tank vent is clogged, then how do I unclog it if the blockage is too far down for me to see?

[valhalla360]

Assuming you didn't get the water from your black tank, overflowing the roof vent is pretty harmless. Most people would just use a garden hose hooked up to a faucet. If it backs up, it tells you what is wrong. If it doesn't after 2-3 minutes, you know it is something else.

[SanMarMor]

ErsandGrrg wrote:
When I was up on the roof, I felt like I could hear water in the vent. I'm afraid that if I put any water down the vent, that it will just overflow. From what I can see with a flashlight, it looks like just a straight shot down. There is nothing in there.

If you put water down your tank vent, and it overflows, your tank vent is plugged.

[ErsandGrrg]

I swear that piece is welded on there. I can't get it off. I even took apart all of the pipes so that I could actually sit under my sink and use both hands and I still can't get it. I'm afraid of breaking something.

[handye9]

newman fulltimer wrote:
look under the sink and you will see a vacum breaker on the end of a pipe unscrew it and see if it drains faster if so it needs replaced

It may look like this. Called "air admittance valve". You can buy them at many hardware stores, Lowes, or Home Depot.

[newman_fulltime]

look under the sink and you will see a vacum breaker on the end of a pipe unscrew it and see if it drains faster if so it needs replaced

[ErsandGrrg]

When I was up on the roof, I felt like I could hear water in the vent. I'm afraid that if I put any water down the vent, that it will just overflow. From what I can see with a flashlight, it looks like just a straight shot down. There is nothing in there.

[laknox]

x2 on vent issues. Bugs, trash, etc...

Lyle

[coolmom42]

It does sound like your gray tank vent is not working right.

If you only have 1 gray tank that would affect everything --kitchen sink, bathroom sink, shower. But I expect in a RV that size there are 2 gray tanks.

Go up on the roof and see if you can run water down the vent with a hose, into the gray tank. Start with an empty gray tank.

[ErsandGrrg]

And, before anyone suggests it, yes I know that the galley sink has a separate tank from the bathroom sink. That was the problem the first time it stopped draining.

[nomad_2971]

Take the cheap black automatic vent off from under the sink and replace it with a Studor Vent or Oatey automatic vent.

Bruce