pool pump couplings

[flymike]

It seems as though, every time I replace our pool pump, I have to glue new couplings onto the fixed piping - because the old couplings are different from the new.
Can anyone tell me:

1. what different sizes are in common use, or being sold in the US?
2. if there are other threads in common use, or being sold in the US, other than NPT?

And, because the couplings I buy never seem to have any identification on them:

• how to identify a coupling, by measuring

Thanks in advance...

 

[Bperry]

It seems as though, every time I replace our pool pump, I have to glue new couplings onto the fixed piping - because the old couplings are different from the new.
Can anyone tell me:

1. what different sizes are in common use, or being sold in the US?
2. if there are other threads in common use, or being sold in the US, other than NPT?

And, because the couplings I buy never seem to have any identification on them:

• how to identify a coupling, by measuring

Thanks in advance...

I’ve found the same thing. Doesn’t seem to be any rhyme or reason. Maybe just need to buy extra to use as spares. Or get rid of the unions if you have to cut and glue anyway.

 

[Jimrahbe]

Mike,

You want to use "Pump Unions"...

I have IntelliFlo pumps, but I think they are the same for all pump's with 2 in plumbing. They screw into the pump like a standard NPT fitting, but they are not tapered and use an O-ring to seal against the pump body..

https://www.amazon.com/Swimables-Whisperflo-Intelliflo-Inground-21063-200-000-2/dp/B0935P4MKW

I can't understand why anyone would install a $2000 pump without pump unions.

Thanks,

Jim R.