The more I read...the more I get....

[fsully]

..confused!

Background
roughly 20 year old, 12K gal, in ground.
Hayward cart filter 120 sq.ft.
Dead pump is a Hayward 1 1/2HP motor, yes, way oversized! ( pool orginally had an attached spa....no longer operational, thanks to orginal owners stupidity...same owner that stopped up bother drains.

So, that leaves me with a single 1.5" pvc to feed the pump, with 2 1.5" returns.

From what I can determine is my piping will handle a maximum flow of 42 GPM. Determining the head is where I am getting confused. From skimmer to pump is approximately 15 ft, with 4 90 elbows and 2 45 elbows. In reading a few websites is seems 50 ft of head is average. Should I use that figure?
With the 1 1/2 hp pump my gauge(clean filter) was roughly 11psi....was that about 30 ft of head? (11*2.31+5)

Any suggestions for a complete replacement pump?

Thanks in Advance
Happy Thanksgiving!

 

[gumarogarc]

If you have an equivalent leng of pipe of 50 ft in tha suction side of the pump and a flow of 42 gpm, with 1-1/2" pipe then the head loss in the suction side is 4.6 ft.

You add the equivalent leng of pipe of each elbow and the pipe, then find in table for 1-1/2" pipe (wich shows head loss for each 100 ft of pipe lenght) the head loss for a given flow and calculate for the lenght you have. In your case is 9.2 ft head loss/100 ft pipe for 42 gpm.

Then you add the output head loss.

Gumaro

 

[duraleigh]

fsully,

I can tell you from several years on these forums that a .75HP pump will do fine. Others are much better at the math if you need to be more precise but I think your answer will still come up 3/4HP.

 

[fsully]

Would there be any problems using a 2-speed 1 HP? I found a Hayward SP2607x102S with the switch, that will be a close match to my current set up. Also found a Pentair 340042 Superflo that would work also. Any pros/cons with either of these pumps?

Any why doesn't Hayward list any electrical specs? Almost every unit I looked at I could find an AMP rating, except Hayward products. But then again I couldn't find dimension on the Pentair products.

 

[duraleigh]

Would there be any problems using a 2-speed 1 HP?

That makes great sense to me. Probably run it on low 12+hours a day or so and then use the hi-speed for vacuuming, etc. You'll save a lot of money on your electric bill.