Please help guesstimate my GPM

[mr ken]

I am looking to get a new pump as my 14 year old motor may be deteriorating...
I posted on another thread that I was looking to get a whisperflo full rated 3/4 hp or 1/2 hp. or a dual speed....
I have only 1 1/2 inch pipes , so gpm are an issue,,,,mas 985 has been very helpful in education me.

I have now just found the paperwork of my current 14 year old pump...

It is a Jacuzzi magnum plus with a magnatec Centurion switchless motor...
It is 1 hp and an SF of 1.2 and is 60hz...

With this unit and 1 1/2 inch pipes, there are 1 suction line 50 feet from skimmer basket,,,,1 suction dedicated line for an automatic cleaner that I have never used or even opened, 2 return lines of 20-25 feet with eyeball jet caps...
no waterfalls or spa or extras..

How many GPM am I putting out with my current magnatec Centurion system..it was installed 1995, so I got good use from it..
Thanks
Ken

 

[mas985]

Because the SF of your current pump is only 1.2, this pump would actually have less flow rate than a full rated 3/4 HP Whisperflo which has a braking HP of 1.25. So my guess would be about 50 GPM with your current pump. The 3/4 HP Whisperflo will probably get you closer to 58 GPM.

 

[mr ken]

mas985,
Thanks
so would I still be ok with the full rated 3/4 hp whisperflow or go with the full rated 1/2 hp whisperflo.
If I went with the dual speed , I would have to go with the 1hp which has the 230 v...The 3/4 dual speed has only 115v set up and I currently have 230v with my current system...
According to Pentair the 1 hp dual speed on hi speed will push 90 GPM at 50 ft of head, so with my 1 1/2 inch pipe this may not be prudent...

Which single spped whisperflo full rated should I go with the 3/4 hp or the 1/2 hp...
Thanks
Ken

 

[mas985]

If you can change the electrical to 115v which is not hard to do, your best option is to go with the 3/4 HP 2 speed. You can simply use one line of the 220v with the addition of a neutral line which should be in the electrical box. High speed would be close to what you have now and low speed would save you 35% in energy costs.

Otherwise, the next best option would be the 1 HP but I would only run that on low speed.

 

[randytsuch]

The neutral line should be white. Hot is normally black, but my 230 hot lines are blue. Ground better be green.

Randy