Pump Advice

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Kenny_Login

Kenny_Login

0
Aug 7, 2016
25
Massachusetts
We're looking to replace our noisy pump, but I wanted to make sure I'm sizing the potential replacement right. Our filter is this one:

96775

96776

So it looks like it's rated at 40GPM. Does this mean the pump has to be 40GPM or less? If so, it seems to limit my options somewhat. There seems to be one Hayward pump (SP1540C), and that's about all I can find.

The pump that's going to be replaced is 1.5HP, and rated at 83GPM according to the manual. I'm very surprised at that. It seems to exceed what the filter is rated for.

Any help/advice would be greatly received. Thanks!
 
Kenny,

Pool pumps are centrifugal type so flow rate depends on the discharge pressure which is determined by the pressure drop in your system. We have a couple of pump experts that can help with the details. I'll call one @Teald024 .

I hope this is helpful.

Chris
 
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The filter you have is rated at 40 gpm at a certain pressure loss. As you push more water through it, the pressure drop goes up. Pool pumps are the opposite, when the discharge pressure is low, the flow is higher. As pressure increases, the flow drops. The system will find a happy point where everything balances out.
Your 1.5hp / 83gpm was operating at much lower flows and it's likely you operated at high pressure.

You should try to match the pump and filter flows. Once way you can go is to get a larger (same size you have) 2speed pump. Most of the time operate on low speed and have lower flows. Only use high speed when needed. You do need to make sure that the pump isn't too big because it can cause issues when backwashing. You don't want flows high enough to lift the sand and have sand go out with the junk/water. LS flow are about half of the HS flows. You should be OK with a 1 or 1.5 hp, 2 speed pump if you weren't having problems before.
We highly recommend the use of a 2 speed pump anyway. It will save you a lot of $$ on your electric bill. When operating at LS the power consumption is about 1/4 of the HS power consumption. Operating at LS will also help with making the pump quieter. When I ran mine on HS, it was noisy, when on LS it was quiet enough to not notice while in the pool.
 
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Good stuff, thanks @Teald024. I had assume the 2 speed ones were not viable, because they all seemed to be on the higher side of the GPM. I'm having real trouble on even Hayward's site, to get the GPM rates in the specs. I like the idea of getting a similar size to the one we have, but running it on lower speed. However getting the exact rates is proving a little tricky. Does this board have any recommendations for which ones are potential options?

Thanks for your input also, @setsailsoon for pinging @Teald024.
 
Seems like these may fit the bill:

PowerFlo® Matrix High Efficiency | Pumps | Above Ground Pool Pumps - Hayward Pool Products

The Power-Flo Matrix has been engineered as a uniquely superior above-ground pool pump. With a single push of a button, this truly versatile pump changes from a vertical to a horizontal discharge and back again.
www.hayward-pool.com www.hayward-pool.com

PowerFlo® Matrix High Efficiency | Pumps | Above Ground Pool Pumps - Hayward Pool Products

The Power-Flo Matrix has been engineered as a uniquely superior above-ground pool pump. With a single push of a button, this truly versatile pump changes from a vertical to a horizontal discharge and back again.
www.hayward-pool.com www.hayward-pool.com

The specs for GPM are here:

PowerFlo® Matrix High Efficiency | Pumps | Above Ground Pool Pumps - Hayward Pool Products

Hayward PowerFlo® Matrix high efficiency pumps are engineered to dependably adapt to the unique needs of a wide variety of above-ground pool setups.
www.hayward-pool.com www.hayward-pool.com

Assuming that the lower speed would be half the GPM, the SP1592 (2 speed variant) would be 43GPM, which is there or thereabouts the same as the GPM of the filter.

Or am I off the mark?
 
That's not really the way they work. Half speed will be much lower flow than half rate. You need to find the pump curve. I'll look and see if I can find it. Normally if you get the equivalent pump any brand will work. Let me see if I can find the curve and get back to you. When you say noisy what does it sound like. Screeching sound could just be a bearing or something caught in the impeller.

Chris
 
You'll want to match the orientation of your pump and the fitting sizes. As Teald024 indicates a either 1 or 1.5 hp should do that is set up for the same voltage and orientation should be an easy replacement.
 
Not really sure how to describe the sound. Like a starter motor maybe? I took it to the local pool store and they serviced it, but it sounds exactly the same. If it's the age of the pool, it could be at most 15 years old. We've saved up to buy a more effecient/quieter one. I'm OK with buying a replacement, just didn't realize how complicated it would be!
 
Kenny,

Power-flow matrix pumps are the high end model for your application. The 1 hp pump should do fine and you can go with one or two speed. Most people prefer 2-speed if you use your pool a lot or plan to switch to SWG at some point for the potential operating cost savings. I don't know if you have a standard orientation but with the Matrix it doesn't make much difference because the head rotates to make matching your existing piping easier. There are a lot of personal preferences that come in to play in your decision. On the cheapest end you can get replace the motor next is a direct replacement for the pump and motor with a generic brand single speed 1 hp. On the high end you can do the 1.5 HP 2-speed Power-Flow Matrix or equivalent with the other major brands. Low end is less than $150 online, High end is about $400. Whatever your final choice is make sure you consider orientation of the piping, pipe size, and match the voltage.

I hope this helps.

Chris
 
Yes, Hayward isn't very good at publishing the pump curves. The Hayward PowerFlo Matrix, 1hp, 2spd variant should be a good pump for your application. The filter is a bit small for it, but I believe the 2 spd model will suit it OK. I had this same model pump and was very happy with it.
It's not as complicated as it could be. I think a lot of people, including myself, put too much effort into sizing the pump. While you think it should be more exact, in reality, it is the pool water chemistry that matters most. Many of us at TFP actually dial down the pump run time to save energy while still maintaining beautiful water. Since the run time is a guesstimate, it makes exact sizing of a pump meaningless. As long as pump, filter flows are in range, you should be ok.
If you want more confusion, my PowerFlo Matrix had a 2hp nameplate on the motor. At the beginning of the season I pulled it apart to make sure there wasn't something in the impeller. I was shocked to find a 1hp impeller inside the pump. Same wet end with a bigger motor.
 
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Great, all this (mostly) makes sense.

So, the 1HP/2SP version (SP15922S) has almost the same specs as my current pump, with the exception of having the lower speed, which seems it will be better from noise and power usage standpoint. My main concern was that I didn't get something *too* powerful, and damage the filter in some way. Given that the pump is rated at 86GPM at 10 ft of head, is that possible?

96802
 
Given that the pump is rated at 86GPM at 10 ft of head, is that possible?
Click to expand...
Not with your setup. Nor is 75 or 58 GPM possible. With a typical AG simple setup with 10' runs, a skimmer, single return with a 3/4" eyeball, 1.5" flex line, my estimate for an operating point would be 44 GPM @ 44' of head. This is about 10% higher than the filter rating.

But it is important to understand what that rating means. It is based upon the ANSI/NSF 50 recommendations which state:
"Filter media and supporting material shall not migrate during the filtration cycle. The filter bed shall remain level during the filtration cycle when operated at the design flow rate."
Click to expand...
So is there a risk the media will "migrate" when exceeding the rating? Possibly. Is it catastrophic? Probably not. Will the filter work better with a lower flow rate? Definitely.
 
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Yeah, I think that pretty accurately describes my setup. Thank you!

If it's not too much trouble, how did you calculate that? I've been trying to understand your post on Hydraulics 101 and reading the INYO pools guide, but it just doesn't make sense to me. I'd like to try and understand it, if possible.
 
Plumbing has a head curve just like a pump does, albeit in a different shape/direction, and where the two curves cross is the operating point of the system. Every piece of equipment such as filters, valves, heaters, pipes, fittings, skimmers, eyeballs, etc. has it's own plumbing curve and contributes to the total plumbing curve. Most web sites on the internet get this calculation wrong by either using too simple of an approximation or by ignoring components in the plumbing system.

I estimated your plumbing curve at approximately:

Head (ft) = 0.0225 * GPM^2

Forgot to mention that some of the tools I use are available in the Hydraulics 101 sticky (see signature).
 
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Not sure if it's OK to revive old threads, but I finally got around to buying (and fitting) the above pump. I had to swap the cable with my old pump, as it came with a regular 3-prong plug, as opposed to a twist-lock. No big deal.

However, I connected everything up, and switched it on. To my dismay, I've found that the pressure on the low setting filters the water just fine, but doesn't provide enough pressure to power our Hayward pool vac. And on the higher end, the pressure is too high, and the pool vac literally suctions itself to the bottom of the pool.

The people I bought the pump from are saying:

"We would recommend a flow gauge or a smaller fitting to reduce the presser coming through."

Is this an actual thing? I'm currently draining the filter with the intention of returning it, unless I can figure out a way to make this current pump work.

Any thoughts?
 
I think what they are talking about is a throttling valve. This is just a simple ball valve between the filter and the return eyeball. You may already have one in-line for maintenance. To reduce the suction on the cleaner on high speed, you would just partially close the ball valve (return side only) until it works properly.
 

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