installing unions on existing PVC pool plumbing

[gm]

I need to replace my pool pump, which has cemented PVC connections currently. I plan to install unions on either side of the pump (intake and output pipes).

Anyone know the trick to doing this so they line up?

It seems like once I put the unions in they will take up some space and thus increase the overall length of the pipe they get put on.

[GT11]

If you can wait until Sunday, I can take a picture of mine because I did the same thing recently. I didn't find a trick, just measured three times, then put the unions on with enough glue so I could adjust them some before it set up.

[bigfishtx]

Why not use compression fittings?

[gm]

what's the advantage of compression fitting, never used one.

[JFolm]

Measure overall union length

Measure depth of the socket in which the pipe will be pressed in to.

Multiply the socket depth by 2 since there is a socket on both sides of the union.

Then subtract that length from the overall length of the union.

The final number is how much pipe you need to cut out for the union to fit.

[gm]

Well, got it done. had to re-pipe a section coming out of the pump discharge cause the union pushed the pump back a but, and there wasn't enough pipe on the intake side to line everything up. Wasn't too bad, letting it cure overnight before firing up the pump....hopefully no leaks!

Thanks for the feedback everyone.

GM

[gm]

Picture of final install