Pool Opening Problems.

[TheGoose]

Suction piping is 2" from the pool. Dual skimmers, one on the near side and one on the far. Pump is at ground level, no more than 3' from the pool level to the pump, probably less than 2' total. Approximately 20-30 ft between the near skimmer and the pump. Filter pressure is ~20 psi clean and I normally backwash about ~28 psi.

Sorry, I was being a little lazy and not running full head calcs. I thought you were interested in an upper limit. But from the picture, it looks like the suction pipe is 2". So if you want full head calcs I need some additional information. If you have already given please post again so I have everything together:

Pump elevation relative to the water level (changes meaning of filter pressure)

Also, I don't remember reading the length of the suction runs. So how long are these and is the diameter 2"?

Filter pressure is 20 PSI correct?

[mas985]

Pump is at ground level, no more than 3' from the pool level to the pump, probably less than 2' total.

This sentence is not making sense to me. Is your pump 3' or 2' above the water line (vertical distance)?

[TheGoose]

Sorry. The vertical distance from the water level to the pump suction. The pump is on a small slab, the pipe rises out of the ground about 12" or so, add in whatever the water level is below that, I would say probably a 2' suction lift. I haven't measured it, but it's pretty minor.

Thanks for all the replies.

[mas985]

Looking back over the thread, one thing I neglected was that you have a top mount filter with a backwash valve. Those valves tend to have fairly high head loss and half of that is before the filter gauge so it is not part of the filter pressure. Anyway if I include that and the suction side plumbing setup including the 3-way valve, here is what I get as an operating point:

Flow Rate (GPM) 69
Head Loss (ft) 65
Energy Use (Watts) 1,839
Energy Factor (Gallons per Watt-Hr) 2.26


Here is the break down of head:

Suction plumbing: 6' = 4' of dynamic head + 2' of static head
Pre-filter backwash valve (1/2): 10' dynamic head
Return plumbing: 49' = 51' of dynamic head - 2' of static head

Hopefully everything is included this time. If you want any more accuracy, you are going to have to take a suction measurement at the pump.

[TheGoose]

Thanks for your info.

Here's an interesting tid-bit: The low speed amperage is right about 1.0 amp as measured with my digital amp-probe. The full speed amps are ~7 if I recall. I know for a fact that the low speed is 1.0 amps, I measured both legs because that sounded too low.

Thoughts?

[mas985]

The CEC measurements for the Whisperflo show low speed power about 24% of high speed power so that is what I would expect. I would be very surprised in the 1 HP Whisperflo only drew 1 amp on low speed. Are you sure you are not running into any accuracy issues with the amp meter? Can you confirm with the house power meter?

[TheGoose]

I'm thinking that since I have the pump restricted back and thus the flow lowered that the amps are lower.

As far as accuracy I think the meter is close.

Here's the specs:
HP - 1~.13
RPM - 3450/1725
Volts - 230
Service Factor Amps - 7.4/1.4
Service Factor - 1.65
Frame - 56Y
Shaft - Threaded
Overload Protector - Auto
Length Includ. Shaft - 13.4


So I think ~1 amp is right on the money if the flow is restricted back.