Quick Pump Question

[Blake1989]

So I’m using a 2-speed 1.5HP Hayward Powerflo Matrix pump and a Hayward s244T sand filter on a 22,000 gallon above ground pool. I have a small question regarding this.

I have one skimmer, and one return. The pump is rated at 91GPM at 10 feet of head. However, my filter has a flow rating of 62GPM according to the vari-flo multiport valve. Wondering if my pump is simply too powerful to the filter on high speed, and I should strictly run on low. All of the pool equipment is located directly next to the pool, and I have no heaters or any other inline accessories installed aside from pump and filter.

The water pressure after backwashing is insanely powerful. The pump does not starve for water if the water level is halfway up the skimmer however. Just want to ensure my pump isn’t preventing proper filtration.

 

[SDor]

It's possible. When I switched from a single speed to a VS pump, I noticed my filter seemed to do much better with the lower flow. If all of your other pool equipment (heater, SWC) and skimmer work at the low speed, I'd just run it on low speed. You'll save money, and it will not harm anything. Or, if the skimmers don't work at low speed, just run at high for a couple hours during the day to skim.

 

[Texas Splash]

Someone like @mas985 might have more hydraulic info to pass along based on your scenario. What is your plumbing size by the way? I use a cart filter, but I have the same pump model and mine is on low speed 24/7. Almost no need to be on high unless perhaps for vacuuming. I don't foresee any major issues for you as long as the filter isn't overfilled with sand. Perhaps Mark will have other thoughts.

 

[mas985]

There is no way your plumbing would that little head loss with that pump.

The PowerFlo Matrix would have the following operating points on typical pool plumbing:

Curve-A 1.5" Plumbing: 53 GPM @ 47' of head
Curve-C 2.0" Plumbing: 66 GPM @ 36' of head

Since you have only one return, the flow rates are likely to be less than what is typical. Also, sand filters are very robust and can easily go above ratings so I would not be too concerned.

 

[Blake1989]

There is no way your plumbing would that little head loss with that pump.

The PowerFlo Matrix would have the following operating points on typical pool plumbing:

Curve-A 1.5" Plumbing: 53 GPM @ 47' of head
Curve-C 2.0" Plumbing: 66 GPM @ 36' of head

Since you have only one return, the flow rates are likely to be less than what is typical. Also, sand filters are very robust and can easily go above ratings so I would not be too concerned.

I wasn’t sure of my head loss, I just posted that spec to give you guys around about GPM. Is there an easy way to calculate headloss? I’m actually curious of what GPM I am running. I’m also using 1.5 inch PVC and 10psi after backwash.

 

[mas985]

Without a detailed schematic of your plumbing, my best guess is below 53 GPM.

10 PSI is already ~26' of head but does not include the backwash valve and plumbing before the filter, including suction side plumbing.

How long are the runs from the pool to the pump?

What is the height of the pump relative to the pool water level?

 

[Blake1989]

Without a detailed schematic of your plumbing, my best guess is below 53 GPM.

10 PSI is already ~26' of head but does not include the backwash valve and plumbing before the filter, including suction side plumbing.

How long are the runs from the pool to the pump?

What is the height of the pump relative to the pool water level?

-Skimmer to pump is about 4 feet of PVC.
-Pump to filter about 3 feet of PVC.
-Filter to return is about 4 feet of PVC.

The pump is on the ground directly behind skimmer by pool wall. Probably 4 feet below water level.

Also, the valve has a max flow rate of 75gpm not 62. Double checked.