I am a pool service tech working on a very old pool for a client. I am fixing what is called a discharge leak currently. I installed a new fitting onto the pump which uses the standard 2" PVC schedule 40 pipe. What I need is something like the following.

Pump Fitting —> 2” PVC (requires 2” 3/4 diameter reducer on this side) —> (reducer) —> 2” 1/8” PVC (requires 2” 1/2 on this side) -> Rest of her System

Essentially I need a reducer that has a diameter of 2 1/2 inch on one side and 2 3/8 inch on the other.

Some things I noticed:

Fittings require 3/8" difference increase from diameter of the pipe to fit it for snug fits. I found this by studying a 2" fitting diameter and that is the difference from a 2" pvc pipe in diameter.

Her System

Her plumbing system uses 2" 1/8" diameter piping for some reason which is making it very difficult to connect the pipes from her current system to the new fitting for the pump which uses 2" diameter piping to fit nicely.

The Question

How do I do this? Where can I buy this type of fitting or how can I make it manually?

Possible Solutions

I did a little research and I have an idea but I don't know if this will work.

Idea #1: There is a technique where you can heat the PVC pipe to soften it. I noticed the diameter of the 2" PVC pipe (for the thin pipe part it's self) is exactly 1/8", this means if I heat the 2" PVC correctly I can warp it possibly to be 2 1/4" diameter since the width is 1/8" equally for the pipe it will expand the pipe 1/8" equally all around making a new size of 2 1/4" which will fit the 2 1/8" pipe maybe? (Assuming I do this procedure first with the 2" pipe and then with the 2 and 1/8" pipe to add another 1/4" around warping it twice)

I think it will fit the 2 1/8" diameter piping because 3/8" extra is required for snug fits from my tests. and 1/8" or + 3/8 = 4/8 or 2 1/2" diameter. I got the idea from this video, https://www.youtube.com/watch?v=QKkMM_b_Mc8 , but not sure if this will work?

Any ideas on this?

Idea #2: They do sell 2 1/2" reducers to 2", however, 2" is not 2 3/8 inch required to fit standard 2" diameter pipes, but I could use the heating technique from above to fit a 2" pipe into it creating the 3/4" difference this way and fitting it in?

  • It sounds like her pipe is some other schedule than Sch40. What do the markings on it say? Commented Nov 16, 2017 at 12:44
  • Also, are your measured diameters ID, OD, or nominal? Commented Nov 16, 2017 at 12:45
  • It’s def schedule 40 Commented Nov 16, 2017 at 14:49
  • FYI, regardless of the wall thickness, the OD is always the same. Always, on all standard pipe sizes.
    – Paul Logan
    Commented Nov 17, 2017 at 16:37

1 Answer 1


A Fernco type coupling may work. These are available to fit a lot of different pipe types. They are available at the BB stores or the plumbing supply houses. They provide a lot of flexibility. I would get a very inexpensive caliper and get the exact outer diameters. Then talk to someone in a plumbing supply house about the right or closest Fernco size. Good Luck. P.

  • 1
    turns out the reason the pipe was 2 1/8" is because it was originally a 2" pipe that had warped from heat. So I'm going to cut farther back and a regular coupling will work in this case. I didn't know PVC pipes can expand like that. Commented Nov 16, 2017 at 18:48

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