Toilet Roof Vent

[Timex]

How high does the pipe need to be in the roof vent? I am wondering if my pipe might be too long to not allow proper venting of the black tank. Here is some pics. I believe it is a 2" pipe. What say you?

[MtnGuy]

Hmmm.....I think mine are about level with the flange. You might be on to something there.

[Timex]

Do you mean level with the white flange where the black pipe starts showing? Should it be flush? And what would keep mice from getting in, a screen?

[VinceU]

Originally Posted by Timex

How high does the pipe need to be in the roof vent? I am wondering if my pipe might be too long to not allow proper venting of the black tank. Here is some pics. I believe it is a 2" pipe. What say you?

The gap between the standpipe and the attached cap should be 1/4 of the pipe diameter for full flow. IE: the gap should be 1/2" clear between them. This is how valves are calculated for full opening also.

[VinceU]

Originally Posted by Timex

Do you mean level with the white flange where the black pipe starts showing? Should it be flush? And what would keep mice from getting in, a screen?

Typing same time as you. Mice will meet their fate if they fall into that soup!

[Timex]

Should I be able to see the pipe with the cap on? Should I cut it some to be able to see completely through the "window" of the cap? Will that be too much?

[Timex]

Eh?

[VinceU]

Originally Posted by Timex

Eh?

Just the upper edge of the pipe at top of window. It's not really crical, a two in vent can handle much more than the input source. Like I said 1/2" or close to that the pipe should be clear of the cap top.

[Timex]

So if I cut off 1/2" from the top of the flange hole that should help my ventilation?

[VinceU]

Originally Posted by Timex

So if I cut off 1/2" from the top of the flange hole that should help my ventilation?

Yes, sounds like cap now is resting on pipe. Cutting 1/2" will be plenty, and help keep out the mice and "fruit flies".

[Timex]

And hopefully the stink bugs!

[VinceU]

Originally Posted by Timex

And hopefully the stink bugs!

Wow I guess the way it was, the only vent for expanding gases was the
W. C. itself eh? Good find!

[jimh]

u don't want it below that hole it is pushed thru on the vent. keep in mind when u start cutting, that pipe moves as u go down the road.

[Superchief]

Be careful how much you cut off, if any. I recently decided to install a cyclone type sewer vent device on the vent tubes on my Unit. In one case I had enough pipe extended to attach the device. In the case of the other vent, it was cut at an angle and I could not attach the device. They had cut the front flush with the top of the cover. I ended up trimming the outside cover so that I could expose enough vent pipe to connect to. I then had to caulk the entire base, as soon as I stabilized the vent pipe inside the cover.

[Timex]

I'll giver the hacksaw boogie here in a day or so. I'll take some more pics to compare with the beginning point.

[VinceU]

Just to clarify you should cut 1/2" down on the existing black pipe. This will leave you with 1/2" gap below the rain cap, thats what you want. You should probably mark you line all the way around and use a sawzall or dremiel cutter to get a decent cut. A hanksaw may have problems with the seal fitting.

[Timex]

Do you mean not having enough room to use a hacksaw?

I'm sure I'll have to sand the burrs of the cut.

[MtnGuy]

You want a little sitting above the pipe in case you want to add a rotating vent system later on. I think you need 1/2" for some of those models.

[VinceU]

Originally Posted by Timex

Do you mean not having enough room to use a hacksaw?

I'm sure I'll have to sand the burrs of the cut.

Yes, cause of the two cap retainers sticking up alongside the vent.

[Timex]

Going back and looking at my pics, I see what you mean. Dummy me I'd probably cut them off too!