best pump for maximum suction lift

[icepond]

Hello,
Greetings from the great white north...
We recently renovated our yard and ended up relocating our pump and filter. We have an inground pool, approximately 14x32, holding about 25,000 gallons.

The pump is now located 50 feet from the pool, but more importantly a good 15 feet above the pool level.
The suction tubing runs relatively straight from the pool to the pump at a gradual incline. No sharp turns, angles, elbows, etcc.

The pump I currently have is not able to prime and start the water flowing no matter what I try. Lines are clean an not blocked in any way. By forcing a water hose into the skimmer line I do eventually get a small trickle of water to flow but not enough to get suction from the bottom drain and create a full vacuum.

Question I have is there a pump capable of providing enough suction lift for my configuration and how can I tell before buying.
HP and GPM are not sufficient I believe.

Any help, recommendations would be appreciated.

 

[HermanTX]

Did you install any check valve before the pump or anywhere along that incline to hold the water in place?
What size suction pipe is it? Also, is connected to the main drain of the pool or to a skimmer or both?

 

[icepond]

Did you install any check valve before the pump or anywhere along that incline to hold the water in place?
What size suction pipe is it? Also, is connected to the main drain of the pool or to a skimmer or both?

Unfortunately.....no check valve. 1 .5 inch pipe suction pipes. One connected to the skimmer. The other connected to bottom drain in the deep end of the pool

 

[mknauss]

To my knowledge, no pool pumps are designed to achieve that much lift.

Let's see if @mas985 or @JamesW can provide any insight.

 

[mas985]

The rule of thumb for most pool pumps is about 6' of unaided lift for priming. You can add some valves on the suction side to increase that a little bit I have never heard of a pool pump being primed at 15' above the water level. I seriously doubt it is possible. But even if it were possible, that amount of lift would create very low pressure in the pump basket and it would be prone to sucking in air all the time.

Unfortunately.....no check valve. 1 .5 inch pipe suction pipes. One connected to the skimmer. The other connected to bottom drain in the deep end of the pool

How many suction pipes are in operation at the same time? A single 1.5" suction pipe will probably never be able to prime at that height and even if it did would likely cause cavitation.

My only recommendation is to move the equipment or at least the pump to a lower elevation.

 

[JamesW]

Can you show the pool and equipment?

Can you access the plumbing near the pool?

Is there a place where you can put just the pump at ground level?

What filter do you have?

Do you have a heater?

 

[icepond]

unfortunately....I get an error saying the picture is too large for the server....but....yes, if we take apart the paving stones we laid down, unearth the pipes we may be able to change the configuration and have the pump closer to the pool and at lower level. Not what we planned but looking like only alternative.

A couple of pool supply stores have "sworn" that the pump they are recommending will work, but I'm reluctant to purchase without at least doing some research

 

[icepond]

Can you show the pool and equipment?

Can you access the plumbing near the pool?

Is there a place where you can put just the pump at ground level?

What filter do you have?

Do you have a heater?

 

[JamesW]

What is the elevation of the pump relative to the surface of the water?

 

[mas985]

What pump were they recommending? Ask the manufacturer if it will prime that high. But again, even if it does, I think you are just asking for long term problems.

Are you sure that is 15 ft. How high is a fence section? 5-6ft?

What about the area one level down from the top?

 

[JamesW]

If you can change the skimmer plumbing to 2.5”, then that would help a lot.

2 skimmers would be a lot better than a single skimmer.

If you can put a Jandy valve in a valve box at ground level, you can shut the valve to prime the pump.

Put a Jandy check valve at the discharge of the pump.

Once the suction line is fully primed, put on the pump lid and open the ground level valve and start the pump.

The check valve will keep the water from falling.

Once the water begins to go through the returns, the static head loss from the returns and the suction will cancel out.

The pump should work at 15 feet of suction head loss, but head loss is static and dynamic.

If you have 15 feet static, you have to get the dynamic as close to zero as possible.

If you can change the plumbing to 2.5" and keep the water flow to 50 gpm or less, then the dynamic head loss will be less than 2 feet and the total suction head loss should be less than 17 feet, which should avoid cavitation.


Is this the level that the pump is going to be on?

If yes, it does not look like it is 15 feet above the surface of the pool.

Make a water level out of 3/8" vinyl tubing to get the exact elevation difference between the pool water surface and the pump inlet.


I would suggest an Intelliflo or Intelliflo XF pump.

I you have a heater, you will need to install a flow switch as the pressure switch will not work.

Some filters can collapse under suction, so if your filter is the cheaper plastic type, you will probably need to use a vacuum breaker after the check valve but before the filter.

If you have a heater, the vacuum breaker will allow the lines to drain and that might cause and issue with the heater if it is running when the pump shuts off because the water will drain out.

Make sure to have a cooldown period of at least 10 minutes from heater shutdown to pump shutdown.

Have a heater start delay of at least 10 minutes from pump start to heater start.

Note: These are not design plans; they are just ideas that might or might not work.

You should do your own design work or get a professional opinion before deciding what to do.

 

[icepond]

What pump were they recommending? Ask the manufacturer if it will prime that high. But again, even if it does, I think you are just asking for long term problems.

Are you sure that is 15 ft. How high is a fence section? 5-6ft?

What about the area one level down from the top?

One recommendation that I am leaning towards is the Hayward TriStar 1.5 HP. It is the only one that mentions suction lift and rated at 10 feet. We would need to undo all the paving and rip out the piping in order to place the pump anywhere else now. An expense I'd like to avoid if possible.

From pool level to where the pump will ultimately sit is about 15ft. Only good thing in my favour is straight lines, no angles or elbow joints and it is a gradual incline.

 

[JamesW]

I would get a Tristar VS or an Intelliflo.

Will you be getting automation?

Can you put a valve at ground level?

15 Feet is a lot to ask for priming.

It might be possible, but it is a major pain to try to do without a valve.

If you are going to stay with 1.5" pvc, you will need to keep the flow low to avoid getting into a cavitation situation.

I would put a vacuum gauge on the suction to measure the suction.

With a VS, you can adjust the RPM up until you hit cavitation range.

Overall, 15 feet is beyond a good design and I would recommend against a 15 foot suction lift.

If you keep the flow to 25 gpm or less, then it might work.

If you need more than 25 gpm, then it is unlikely to work well.

25 gpm puts you at 4 feet dynamic or 19 feet total.

 

[icepond]

Thanks James, must admit....have limited knowledge of water dynamics and all the engineering that goes into making pumps work. Scouring the internet for any pump that might work, came across a Sta-Rite Max-E-Pro (Pentair) that claims to have Self-priming - Suction lift up to 15' above water level.

Looks tempting....but everything I am reading here seems to suggest I'm gambling somewhat on an expensive pump that may ultimately prove to be ineffective for my use.

 

[JamesW]

A single speed pump will probably not work.

15 feet is really too much to expect a pump to prime.

Can you increase the pipe size?

Can you put a valve on the suction lines at ground level?

 

[icepond]

HI James,
I do have shut off valves at the pump on both suction lines. And I am looking at a 2 speed model. Not sure variable speed is worth the extra cost. Pool season up here is not that long, so pump won't be running much.

 

[JamesW]

Can you put a valve on the suction lines at ground level?

 

[JamesW]

At 15 feet, it is probably not going to work.

 

[wireform]

Not sure how you figured 15 feet. Counting the wall blocks which I see 12 high @10" each gets you to 10 feet.

 

[icepond]

Not sure how you figured 15 feet. Counting the wall blocks which I see 12 high @10" each gets you to 10 feet.

LOL....good eyes !! was adding some elevation just to be on the safe side. I figured somewhere between 10 and 15 feet is where I'd land and looking for a pump that had the highest suction lift rating. Odd that pump manufacturers do not provide that specification. I've seen only two pumps advertised by the seller that provide that rating. The Hayward Tri-Star (10 feet) and the STA_Rite Max-E Pro (15 feet). Question still remains if I am at the fringe of the pump being able to prime ?