Pump pressure

[slade8200]

I recently just got a new 1.5HP Hayward pump unit to replace my existing unit which was leaking. This is hooked to a tank with the DE grids (Splash-Pak) inside. With our original pump with a fresh DE coat, the pressure was 13.5 psi. Then when the output jet was weak (time for a DE change) the pressure would be about 16.5. With this new pump, the beginning pressure is about 16.5 and it gets to about 21 when the DE needs changing. I don't know the original HP of my motor since it was never printed on the label. It was a Magnetek motor but I haven't been able to find any documentation on it. What are some signs that this new motor might be too strong? Thanks.

[slade8200]

No comments? I am confused as I hear different stories from every pool store I talk to.

[PoolDoc]

'Normal' pressures vary from pool to pool, based on equipment and piping. By the time the owner is looking at it, it's a 'done deal' and usually unchangeable without equipment or plumbing modifications.

Not too many here are prepared to do hydraulic design calculations -- which is what's required to actual analyze whether your pressure is 'correct' -- and even if we were it's time consuming, a commodity in short supply for us at present. But even beyond that, few pool owners are prepared to accurately and completely supply the information required.

So . . . in theory, some one could answer you. But in practice, not so much.

You can check online, to find the manual for your filter, but it sounds like you are within tolerance levels for most filters. Alternatively, you can get the 1HP impeller and diffuser for your new pump and install those (along with a new seal) and lower your pump's output and electrical consumption.

Ben

[slade8200]

I didn't think intense calculations were necessary. I have seen people on here say "sounds like your pump is too big", I just wanted to see if I was in that boat.

[PoolDoc]

The calculations aren't "intense" -- nothing but adding and multiplying is required. You can get started here:
http://www.engineeringtoolbox.com/eq...hod-d_804.html

There is a little manual curve fitting and picking, when you get to the end, but that's all visual, not calculated.

The problem is, it takes good info in, for all that adding and multiplying to come up with the right answer. That means you MUST know what valves, fittings and piping make up your loop. No matter how hard you try you can't get good circulation through a 1" pipe! Think that's an exaggeration? Take a look sometime through the primary port in Hayward inline chlorinator!

Best wishes,

Ben