Advice Please: Small Variable Pump for Low Head Inground Pool

Clemenski

New member
Jun 24, 2018
4
Toronto Ontario
Hi,

BACKGROUND: I am looking for some input with sizing a replacement variable pump for my simple swimming pool. I have a 1.5 inch plumbing, a single suction line (from a skimmer), and two returns in a 180000 gallon in ground pool. Currently I only have 115 to my pool shed, but I ran new conduit to it last year so I can easily pull 230 if necessary. After doing some rough calculations on my head loss, I realize I can get away with the smallest pumps and my 1hp single speed is oversized compared to the efficiencies that can be found in modern pumps. Frankly, a 1/2 hp high efficacy Pentair whisper flow WFE-2 on a timer would probably due the trick but I am leaning towards a variable speed because I like the idea of continuously circulating my pool at the lowest rpm possible (95% of the time). The only equipment that I have that demands a minimum flow is my millivolt heater (25GPM) and I only turn on and off the heater manually on rare occasions to bump up the heat before a get together or weekend.

QUESTION: Is there any advantage to using a small 0.85 HP variable pump over some of the larger 1.5/1.65 HP variable pumps? In my local area the 0.85 HP variable pumps are not stocked anywhere and command the same or higher prices than the 1.5 HP models. Ditto for the smaller 2 speed pumps being only 25% less expensive than a variable pump when I factor in the external timer/switch (plus the warranty is better on the variables and my credit card doubles the two year warranty period).

I was thinking of buying a Pentair Superflow VS 1.5 hp that is larger than my needs and program the steps so the pump never runs over roughly 2400 RPM or whatever minimum RPM necessary to maintain a flow rate of no more than 40-50 GPM. I am not sure if there are any concerns for start-up, priming, etc.? The Pentair comes in cheaper than the smaller sized variables and services both 115 and 230.

Here are the pumps I am comparing:

Jandy FloPro VS 0.85hp with controller: VSFHP085JEP
Hayward Super Pump VS 0.85hp: SP26115VSP
Pentair Super Flow VS 1.5 HP: 342001

I appreciate the vast pool of wisdom that makes up TFP.

Clemenski
 

JamesW

TFP Expert
Mar 2, 2011
17,381
I would go with the Pentair Superflo. Even though you won't use full speed, the higher hp pump will be quieter at the same flow rate due to a lower rpm
 

setsailsoon

Gold Supporter
LifeTime Supporter
TFP Guide
Oct 25, 2015
2,100
Stuart/FL
Clem,

Congrats! You've obviously done the homework on pump sizing and will reap the rewards of this approach. Can you please fill in your signature with all equipment and model numbers? It will get you quicker response from our experts. Here's how do it. Also a layout showing distances of electric runs equipment pad from pool etc will be helpful. Photos always help too.

Are you planning to DIY or purchase from the internet? If so Jandy will not warranty. I like Jame's recommendation best anyway. You also have the advantage that you can run higher speeds as needed to clean bottom (assuming you have a water powered cleaner) and skim if needed. If it were me I'd go for the 230v setup since, amperage is lower, wire sizes are more manageable and you already have the conduit.

Good luck!

Chris
 

Clemenski

New member
Jun 24, 2018
4
Toronto Ontario
Hi All,

It sounds like there is no real concerns with up sizing, which probably explains why no one seems to stock the lower power variable pumps in my area. I was worried that the larger variable pumps might start at their full RPM after a power outage or something putting too much strain on my small 1.5 inch pipes.

I manually dose my pool with liquid chlorine; have no intentions of doing it any other way.

Distances to the pool shed from my electrical panel is 25 feet.

I intend to DIY. I am located in Canada and it seems like Pentair will also not support warranty claims for DIY unless it is a "qualified installation".

I will likely purchase from my local retailer cause I want them to stay in business cause I appreciate the short drive for liquid chlorine.

Thanks for the advice!
 

JamesW

TFP Expert
Mar 2, 2011
17,381
Even at full speed, the pump won't generate enough pressure to damage anything.

When you get the pump, go into settings and set the maximum speed to 2,400 or whatever you want.