Drains or vents?

[TryingToLearn]

Day's like today I wish I was a plumber.

2016 Sunseeker 2400W MBS
(new to me)

Sanitized fresh water system. Found out the kitchen sink drains slowly then backs up. Thought might be partially because MH wasn't level but logic says sinks are still higher than tanks. Grey tank wasn't even 1/3 full. Bathroom sink seems to drain fine no matter how long it ran. Shower backs up.
Ran snake from kitchen trap several feet, till it hit a turn I couldn't negotiate, with no result.
Opened vent on roof and ran snake down with no result.

Now the fun - finally was able to get bathroom sink to start backing up about 2" deep. Once the faucet was shut off, it drained. Then it came back to 2" deep & drained again. About 45 seconds later it came back & drained. I didn't notice a difference in level in kitchen sink or shower during this. Definitely heard gurgling preceding old faithful.

Opened the grey tank valve & everything drained quickly.
Tried it again with similar results.

Easy answer = don't use the sink or shower. Maybe someone has a more rewarding answer for me?

Thanks.

[Dwilcox]

Check your vent valves under sinks. Should be one under Kitchen sink and bath sink. Roof vents only go to tanks. Traps must have there own vent to drain properly. Will get a photo of ours so you can see what I am talking about.

[Dwilcox]

Kitchen

Bath

You can try removing and see if sink drains better. If drain is plugged, remember, water seeks it own level so if it is above the adapter the valve screws into, water, water everywhere. I am a plumber so don't ask how I know.[emoji57]

[TryingToLearn]

Thanks for the pics Dale. Gives me a clue what to look for.

My bathroom sink doesn't have a vent on the trap. The kitchen vent is only visible by camera shooting blind. I see a white glue line, teflon tape or joint compound at the top joint, not sure which. Does this vent unscrew by hand? What should I have on hand to reinstall it?

I don't need no stinking water under the sink!

[Dwilcox]

Yep, just unscrew, you can use Teflon to reinstall. If it is stuck closed, and you need to replace, you can get at HD or Lowe's. That one may do both traps. Can you see on the other side of the wall to look at the piping?

[TryingToLearn]

Cannot see other side of wall. Removed the valve and it didn't resolve the issue.
Out of my trying to learn, the valve works backwards to my logic. it is normally closed and to open it you would need a vacuum for the valve to open. Of course, this could mean it's bad.

Back to main subject... We are leaving tomorrow and the other half says she wants a working shower. My logic says the shower is lower than either of the sinks therefore it should be backing up into the shower. It's not so I must assume there is a check valve for the shower drain as well.

Short of taking walls apart, I'm willing to try anything else tonight. The attached pic is a better view of what's under the bathroom sink.

Thanks
-Bob

[rebeltown]

I'm no plumber but I would put a pan or bucket under the traps, open them just to see that they're clear.

[Dwilcox]

The valve is working as it should if it opens with a vacuum. Can you see the trap for the shower? As rebel said, take the traps apart and make sure they are open. You can also make sure that the Grey is empty then leave that valve open with a bucket under it and try running water into the shower and see if that makes a difference.

[Dwilcox]

Also remove trap from sink, put bucket under it then run water into sink, does it drain right out?

[TryingToLearn]

yes, i had the trap out the other day to run the snake.
If I can get a snake eye camera to look into the walls, what am I looking for?

[TryingToLearn]

Originally Posted by Dwilcox

The valve is working as it should if it opens with a vacuum. Can you see the trap for the shower? As rebel said, take the traps apart and make sure they are open. You can also make sure that the Grey is empty then leave that valve open with a bucket under it and try running water into the shower and see if that makes a difference.

If the grey valve is open, everything drains as it should.

[TryingToLearn]

Originally Posted by rebeltown

I'm no plumber but I would put a pan or bucket under the traps, open them just to see that they're clear.

They must be clear since everything works fine if the gray drain valve is open. I had already removed the kitchen sink trap and it was ok.

[llr]

If everything drains fine with the gray dump valve open then it sounds like the grey tank vent. If it is clear it could be too low in the tank

[TryingToLearn]

Originally Posted by llr

If everything drains fine with the gray dump valve open then it sounds like the grey tank vent. If it is clear it could be too low in the tank

I'm almost afraid to ask - how do you determine this?

If the grey tank is 2/3 full, once we open the valve, everything drains as it should.

[llr]

Good question, unfortunately I don't have a solid answer. Can you see the top of the gray tank where the vent enters the tank. This could involve removing draws or panels.

[dalford]

Are you going to have sewer hookup where you are camping? If yes, then open grey tank valve, at least while showering if you can't resolve before you leave.

[Dwilcox]

If you take a tape measure up to the roof, stick it down the vent. Hook the bottom of the pipe and see how long it is. Then push to bottom of tank. You should have 4 or so inches between the two.

[TryingToLearn]

Originally Posted by llr

Good question, unfortunately I don't have a solid answer. Can you see the top of the gray tank where the vent enters the tank. This could involve removing draws or panels.

I believe the tank is located under the bathroom sink but can't see anything from inside that I'm aware of. I believe the tank vent is the diagonal pipe under the sink in the picture posted in msg #6. I will take another look.

[TryingToLearn]

Originally Posted by Dwilcox

If you take a tape measure up to the roof, stick it down the vent. Hook the bottom of the pipe and see how long it is. Then push to bottom of tank. You should have 4 or so inches between the two.

Clever and logical. I will have to wait till daylight to try this. I'm betting this is not the issue however, based on the fact that it would have always done this and it's probably unlikely the pipe had lowered itself. Daylight will tell.

Meantime, taking a 2 1/2 foot snake eye camera for a test run after I drain the grey tank.

[Dwilcox]

If that angled piece is the vent then ya, it can't drop. Just a heads up. If you do the tape measure thing you will feel it go in then light stop, a little push it will go in more, by the look of the angle piece about 2 feet then light stop again. Little push it should go in easy till bottom out. If it hooks the pipe it WILL be a pain to get out so I will not recommend that you do this. If you can get the camera into the tank from the outlet side you should see if the vent is in the tank to far. Best of luck and let us know what you find.