Installing new shower drain, need some help.

[Jay EHRGOTT]

Ok took out the old cast iron drain in order to center the drain as I am redoing the
entire area. Used a Fernco 1056-22 to go from the cast iron to the 2" PVC, will re cut the
cross piece as I my cut was a bit rough on one end. I have a bit more than the 1/4" per
foot required and I think everything is good, but I wanted to make sure I'm not missing
anything, thanks for the help. Hope you all have a blessed and safe Thanksgiving.

 

[Jadnashua]

How far away is the vent? The maximum distances are based on 1/4"/foot slope. It may just work fine if the vent is close enough. The rationale for that is to ensure that there's always a path for air along with the drainage to break the suction and prevent the trap from fully draining.

 

[Sponsor]

 

[Jay EHRGOTT]

If I had to guess I would say the vent is 8-10 ft away, I'm guessing the location but I can look on the
roof in the morning and be more accurate. As the drain line is only being extended 8" I don't think
the vent will be a problem, but I could be wrong. Oh, thanks for the help.

 

[Jadnashua]

Where it exits the roof may not be where the vent is for that run as once it goes up enough, it can also run horizontally, or, if you have an attic, it could make that connection in the attic before going out the roof.

Depending on the plumbing code adopted in your state/county, the vent for a 2" pipe is typically a maximum of 60", so 8-10' wouldn't cut it. At 1/4"/foot, 10' would be 2.5" from the outlet of the trap to the vent - much larger than the diameter of the pipe. One of the codes used in the US would allow that distance, but IMHO, best practice would be that 60" (1.25" of drop, leaving 0.75" of air minimum once the flow slows to break the siphon on the trap so it doesn't run dry.

 

[Jay EHRGOTT]

My brother and father were union pipe fitters, I've done a lot of plumbing in my life so
I know how vents work, but if I see it on the roof and then find it in the attic, there are
only so many places it could be.

I understand your reasoning, however I am all but certain there is no vent within 5',
mostly because there isn't a place where it could be with a 5' radius, the system worked
for 45 years and the trap held water. I would be really surprised if this trap doesn't retain
water, but I will test it tomorrow and see.

 

[WorthFlorida]

https://codes.iccsafe.org/content/FPC2017/chapter-9-vents

 

[Jay EHRGOTT]

I'm at 8', the vent is behind the vanity , could be a bit further but
I don't think so. I'm putting a wall to wall mirror so I could poke some
holes to find the exact spot.

 

[Jay EHRGOTT]

After looking at the setup and thinking about it for a bit, I think the shower is wet vented
through the toilet.

 

[Plumber01]

I would recommend using a mission band specifically for transitioning from cast to plastic.

Shielded rubber couplings are required inside a building in my area FWIW.

 

[Jay EHRGOTT]

I thought the same thing, to use a shielded transition piece, I called Fernco directly and they
told me to use the 1056-22. The old trap install was done using a shielded piece, so I think
I will swap it out, will have to see if my local supply house sells mission products, thanks.

 

[Plumber01]

Fernco makes them too. Look for the Pro-Flex couplings, the 3000-22.

The one made by Mission is the cp-200.

I was using them term mission interchangeably. I don't prefer one over the other. You can find mission and fernco products at the big box stores too.

 

[Jadnashua]

You can use the unshielded connection when it is underground and backfilled...done correctly, it keeps the two ends of the pipes aligned which is the issue when used above ground. It's that misalignment that causes issues. The banded coupling prevents that from happening.