Where is the vent?

Topic: Where is the vent? (Read 838 times) previous topic - next topic

Where is the vent?

April 15, 2016, 10:42:02 am

The bathroom sink has been getting slower to drain, so a few weeks ago I pulled the trap, thinking it was getting clogged. It was clear, and when I put it back together the sink drained properly. Lately, though, it is getting slower, so I did the same thing, but this time there was no improvement. I figured that the roof vent must have gotten clogged with leaves or something. Just now I climbed up to see, and there is no vent in that area. Where is it?

Re: Where is the vent?

Reply #1 – April 15, 2016, 11:23:43 am

I believe it goes through the floor to the closet closest to the pocket door and up to the roof. Mine has a 1/2 false wall wherein lies the plumbing.

Re: Where is the vent?

Reply #2 – April 15, 2016, 11:41:27 am

Thanks, Twig. Jo Ann and I pulled everything out of that closet and checked. It looks like the vent might be on the street side of the coach. Since the bathroom sink is the only one that has a problem I'm guessing that the vent isn't the issue. Most likely there is something that is partially clogging the line between the bathroom sink and that pipe.

Without tearing the whole bathroom apart, it looks to me like the pipe goes straight across from the sink to behind the drawers, then straight down, then straight back across under the floor. Does that sound right?

Do I dare put some Drain-O type stuff down there and then immediately dump? We have FHU here, so that's not a problem. Looks like we need to go into town to Wal-Mart soon anyway.

Re: Where is the vent?

Reply #3 – April 15, 2016, 11:53:27 am

I wouldn't use a chemical, they usually build heat not good for abs. I use a small snake on my rental house when the bathroom sink gets plugged. It is a Rigid brand and is 15 Ft. long has a spiral hook that when you turn it catches the hair or whatever object is blocking the pipe. It was sold at Home Depot. Any small snake will reach in a motorhome.

Re: Where is the vent?

Reply #4 – April 15, 2016, 11:59:36 am

Do you not have a "top hat" type of vent under the sink? Ours has one under each of the sinks as well as in the washer hookup cubby in the back of the closet. There are two vents on the roof, and I believe one is for the grey tank on the curb side (the one that goes up through the closet), and one for the black tank on the street side. There are ABS tees that connect to the vent pipes that go up, so the roof vents on the street side may be doing the black tank as well as the waste water and the top hats are just to supplement the roof vents. However, I know there is no ABS pipe that crosses from one side of the coach to the other on our coach.
Don

Re: Where is the vent?

Reply #5 – April 15, 2016, 12:11:21 pm

David,

Here is a link to an air admittance valve that Don is referring to under your sink. They come in many styles and cost, this is just a basic one but will give you an idea what to look for. Shop Keeney Mfg. Co. 1-1/2-in Plastic Mechanical Plumbing Air Admittance...
Pamela

Re: Where is the vent?

Reply #6 – April 15, 2016, 12:12:30 pm

Not sure if you have the same floor plan as I have but mine is in the "laundry hamper" behind the toilet. It's a one-way air admittance valve. I have a total of 4 in the coach. I've replaced all of mine. The rubber in the valve can get stiff and at only $6 bucks a pop why not.

Oatey 1-1/2 in. ABS PTC In-Line Cheater Vent-39012 - The Home Depot

Some folks like the STUDOR better but at 3 times the price I'll stick with the Oatey.

STUDOR Redi-Vent with ABS Adapter Valve-20362 - The Home Depot

These just screw on so you could easily test by removing it. (sometimes requires channel locks to remove) Then checking if water flows better.

see ya
ken

Re: Where is the vent?

Reply #7 – April 15, 2016, 12:33:45 pm

Thanks, Ken. Putting the vent there makes more sense than running the drain pipe all over the coach. I'll see if there is one of those vents back there. That's certainly easier to change than going up on the roof.

Re: Where is the vent?

Reply #8 – April 15, 2016, 12:53:29 pm

Now that I've thought about it a little bit more I don't think that's your problem. These vents usually fail open letting odors from the tanks into the coach.

Just remembered that my bathroom sink was running slow a while back, I pulled the p-trap and found nothing. Checked the sink plug thingy and found lots'o hair & crud. Removed and cleaned and sink started running fast again. Check there if you haven't already.

see ya
ken

Re: Where is the vent?

Reply #9 – April 15, 2016, 01:26:58 pm

Quote from: kenhat – April 15, 2016, 12:53:29 pm

Now that I've thought about it a little bit more I don't think that's your problem.

That's what I love about forum members, we'll post something off the top of our heads, then either delete the post and start over or re-post when we realize the "cart mite have been before the horse".

Re: Where is the vent?

Reply #10 – April 15, 2016, 02:00:31 pm

Well, I can certainly check the drain plug. I wondered about the vent behind the toilet, as it seems a bit low. On the other hand, the route I described above does seem a bit convoluted, but then I don't know how many entrances there are for the grey tank. If there is only one, it would make sense that the sink and shower would run to the other side, where the kitchen sink and washer would be.

If I don't find a clog at the drain I'll borrow a small snake and see what I can find that way. Love these plumbing problems.

Re: Where is the vent?

Reply #11 – April 15, 2016, 02:34:34 pm

Ken, I think that vent behind the toilet is for the toilet, not the sink. We have a walk-thru bath, so when I'm standing in front of the sink I'm facing the front of the coach. The drain pipe goes to the right (toward the street side) and disappears into a wall. There are three drawers below the sink counter, but there isn't room for my fingers to release the catch on the top drawer, and the other two run into the toilet. Above the counter there is a triangle formed by the two bathroom walls and a hypotenuse. I first thought that the vent pipe went up that chase, but since it doesn't come out the roof I wondered where it might go. Now I'm wondering if the vent is actually in that space. There is an electric outlet there, so maybe I should kill the power to that outlet, pull it out, and see if I can see anything behind it. The panel that forms the hypotenuse doesn't show any obvious attachment, other than the caulk, but I would assume that if the vent is behind there, and if I can get it loose, I can easily change the vent.

Re: Where is the vent?

Reply #12 – April 15, 2016, 03:36:57 pm

I think the vent behind toilet is for shower and there should be another vent under the sink, maybe to to right above top shelf. If you only have 1 roof vent outlet then there must be a drain line going under floor to tank or other side vent.
JohnH

Re: Where is the vent?

Reply #13 – April 15, 2016, 03:47:06 pm

In which case the problem is NOT the vent, since the other drains are fine. Later today I'll take the stuff out of the sink and see what I can see, and take the drain apart.

Re: Where is the vent?

Reply #14 – April 15, 2016, 06:54:17 pm

David, you just need to remove the rod and screw cap on the back of the drain under sink and pull that rod out. This releases the pop up which now can be pulled out of the drain from the sink. More than likely there will be a lot of sloppy messy black crud in there so while it is out flush the sink drain with some hot water and use a flashlight to make sure that it is actually clean.
JohnH

Re: Where is the vent?

Reply #15 – April 15, 2016, 07:41:38 pm

Quote from: kenhat – April 15, 2016, 12:53:29 pm

Just remembered that my bathroom sink was running slow a while back, I pulled the p-trap and found nothing. Checked the sink plug thingy and found lots'o hair & crud. Removed and cleaned and sink started running fast again. Check there if you haven't already.

see ya
ken

That is the problem every time our bathroom sink starts to drain slowly. That little plug thingy unscrews on our sink, you might try that.

Roland

Re: Where is the vent?

Reply #16 – April 15, 2016, 09:34:02 pm

Yes the top of the stopper on ours unscrews also so you can clean out that guey mess. it is a left hand thread on ours

Re: Where is the vent?

Reply #17 – April 17, 2016, 03:13:59 pm

I should have posted this earlier, but, yes, it was crud in the stopper. It took longer to empty the cabinet than it did to fix the problem.

I still don't know where the vent is, though.