A variable speed pump can be used with 1 1/2" pipes, though it isn't usually recommended. The variable speed pumps startup at a fairly high speed, which can put a strain on older small diameter plumbing.
Jason, (or others)
I've been thinking hard about replacing my 1 HP pump with a Intelliflo VF. Doesn't my 1 HP single speed pump put a big strain on my 1.5" inch pipes? (I actually think I may have had a 3/4 HP pump there when I moved in 33 years ago, but am not sure.)
Doesn't the VF run at low speeds and flows, thus putting less strain on your system?
And isn't the Priming Mode flow a setting you can make, again putting potentially less strain on my pool piping?
I was thinking of getting a variable speed, and likely the VF, for the energy savings it would deliver. I calculated a couple of different ways, and think it's about $500 a year for me.
And I thought an added bonus would be the less strain it would put on my pool system.
Do I have this wrong?