Need new pump either 2 speed or variable speed

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Laker4ever

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Jul 17, 2009
61
Hello all,
As a result of my impatience + leaking/rusted pump i probably need to buy a new pump and thus would like to pick the best for my setup.
(thread on why i probably need new pump)
tried-to-fix-my-old-ultra-flow-pump-now-need-a-new-pump-t27097.html

Since I can get a $300 rebate if i buy a two speed pump WITH controller, or variable speed, i would not even consider single speed.
My existing pump was the Pentair/American products Ultra Flow 1.5HP Full rated. From its manual I believe it is curve D.
I have solar panels mounted on 1 story house roof at a height of about 16 feet at peak. Total of 10 Fafco panels in two groups (on two roofs) plumbed with 2" PVC. From the solar diverter at the pad, it runs about 80 feet then 8 feet up into the 1st panel. From the last panel, there is a run of about 80-100 feet of 2" back to equipment.
All the plumbing is 2".
Suction includes 12 feet from skimmer that has two equalizer drains on the wall 3 feet apart. and 1.5" line that comes from a cleaner into 3 way jandy and into the pump. After the pump it goes to a 60 sqft DE Pentair 4000 filter, than to a check valve and into the 3 way solar diverter. The return goes from the TEE to a pool heater (325 kBTU), then to my IC40 and to the pool with 2" that goes to 4 eyeballs.
With filter clean and (old ultra flow) pump fully primed:
Without solar:
Filter at 15-16 PSI
With Solar:
Filter at 26-28 PSI
Now I'm not totally sure if the pump was perfectly sized, but it sure did the job. ( I think running at 30 PSI is not optimum...)
From my calculations it seems like my head was about 45 with no solar, and 68 with solar. using curve D, I was at 105 GPM with no solar and about 78-80 GPM with solar. Please correct me if I'm wrong.
The filter has a 116GPM as a flow rate (optimal flow rate??)
The intellichlor IC40 is commanding flow up to 25-105 GPM... (or use bypass)

I'm debating between the WhisperFlow WFDS-6 (1.5HP FR FR at high speed little stronger than my old one) , WFDS-4 (1.0 HP little weaker than my old one), or the Jandy ePump 1.5HP that could be tuned to my application "on the fly"
I tabulated the Flow rates:

HEAD Ultra Flow WhisperFlow 1.5HP WhisperFlow 1.0HP ePUMP at max RPM
40 110 124 100 147
50 100 112 90 132
60 90 98 76 106
70 75 85 63 85
80 60 65 43 NA

I found that i can get the:
Whisper Flow 1.5 HP or 1.0HP with 2 speed controller (intermatic P1353ME for $180) for total $785 (different vendors, but price was pretty much same for 1.5 or 1.0) (remember i need the 2 spd controller to get $300 back from DWP)
ePump with wall mounted controller for $1089

What should i do? go with the 1.5HP 2 spd, and see even higher pressures with solar ( I assume I will run high speed for solar, low speed for filtering), or get the 1.0HP 2 spd, and thus save money when operating with solar albeit run little longer now I'm not sure if there will be any savings, maybe just less stress on the plumbing) Will the 1.0HP be enough? I'm afraid its low speed might be too weak to even use for filtration only...
Or maybe invest $300 more to get the ePump. I pay about $0.12 per KWH.


huge thanks for the help....
 
The $300 price difference will be made up quite quickly on the E-Pump plus it gives you quite a bit of flexibility when setting flow rates. The downside is that there is definitely more to go wrong but reliability so far doesn't seem to be an issue with these pumps.

But if you do go with a two speed, I wouldn't go with anything more than a WFDS-3/24. You shouldn't need anything more powerful. Lower HP pumps will always save more money that high HP pumps even with the longer run times.
 
mas985,
You claim that the $300 extra would be made up quickly. Is that versus 1 speed pump or 2 speed pump.
The way i see it is that i would probably pay the premium of $300 for the ability to tweak with the flow rates....
AT $0.10-0.12 per KWH at DWP, I don't think i would get such big savings of ePump vs. whisperflo 1HP 2 speed.
(Maybe 20 year payback...the equipment would be long gone...)
My sole and only problem is to hit the exact figures. My setup is not complicated...
I have solar panels, 35k pool and navigator cleaner. And i was running a 1.5HP full rated pump single speed before. Only now, i realize that this pump was oversized, wasted money and stressed the equipment (plumbing... copper that leaked last year...)
 
I meant vs the 2 speed. At $0.12/kwh here are the 120 month runtime costs including the cost of the pump:

E-Pump = $2926 (includes $1089 for pump)
WFDS-24 = $3391 (includes $785 for pump)
WFDS-26 = $3679 (includes $785 for pump)

Break even for the E-Pump vs the WFDS-24 is around 40 months of runtime, then the E-Pump starts to pay for itself. Payoff is sooner if you average more than one turnover per day. If the pool is open only 3 months out of the year then 40 months is really 13 years.

I also assumed 25% at full speed and 75% at low speed.
 
mas985 (Mark),
The WFDS-24 is exactly the same as WFDS-3 (WFDS-26 = WFDS-4) Right? ( I remember reading on the forum that they have slightly different powers with the Full rated stronger than Up rated. (WFDS-26 < WFDS-4)
I don't have 100% confidence that 3/4 HP pump can work my solar... (especially at its low speed) If I get it, I might end up running its full speed...Maybe 1.0HP half speed might be enough...

Still, all this just leads me to favor flexibility and i do see how those variable pumps are essentially "for dummies" as you pretty much can't make a mistake in sizing it...
So I would compare your numbers of $2926 vs $3679.
I might not not use the pool 12 months a year, but here in So Cal, we don't usually close the pools, and therefore still need some minimal filtration of probably 50% of peak usage. Please correct me if I'm wrong...
The $784 and $1089 are the best prices i was able to find (delivered , taxes included) for the 2 speed with intermatic P135 and ePump plus the controller respectively.
I'm leaning towards the ePump, with some doubt still on its reliability (complex) and huge size. That thing is 33" long and 1" higher than my current Ultraflow pump (25" long).

As a side note, I'm planning to build a custom automation system based on micro processor, that will control the pump, with speeds, fountain, deck jets, solar, lighting, color logic lights, etc. I hope to contribute to this forum on this subject extensively.
.
 
The WFDS-3/24 should work fine for solar and yes the 3 is the same as the 24 and 4 the same as the 26. I'm not sure why you think it wouldn't. By comparison, I am now using a 1/2 HP pump for solar on a two story roof so I am pretty confident the 3/24 would work fine for solar.

But I do agree the flexibility of the EPump is a plus and combined with the cost savings should put it at the top of the list of choices.
 
Currently with my 1.5HP ultra flow that is, according to the curves, just slightly less than the whisper flow 1.5HP as far as flow rate at same head. With it, I had sometimes issues o run the suction pool cleaner when solar was on. I have a jandy valve at the pump input that selects between the the cleaner or the skimmer/drains. When the filter was 80% clean, i hat to put the valve at about 80% vacuum, 20% skimmer to have decent movement.
So....taking from this downsizing to 1/2 HP would not improve that....
But most importantly, i bet that when you run solar, you do it at high speed. Can you confirm that? I would be very surprised if you can run solar to 2nd story with 1/2HP at low speed.
 
mas985 said:
The WFDS-3/24 should work fine for solar ... I am now using a 1/2 HP pump for solar on a two story roof so I am pretty confident the 3/24 would work fine for solar.
Click to expand...

mas985: I have the WFDS 3/4 pump and I'm considering solar down the road. I have a single-story house. Back when I was getting quotes, the solar guy told me I need a variable speed pump for solar, but it sounds like perhaps I don't! I currently run my DS pump for 2 hrs on high and 6 hrs on low (small pool, only 10k gal). Based on your experience with your 1/2 HP pump, do you think could I keep it at that with solar installed? Or would I need to run it at high for longer?
 
terriolsen,
Since you have a 2 speed at 3/4 HP depends on the # of panels. !st story at high point is probably 15-18 feet. Say you have 10 panels at 4 GPM, I'm sure that you would be able to run 40 GPM at your high speed. At low speed I'm not sure....
 

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If you use a pool cover then 2 hours may enough on high speed to maintain pool temps. I generally will run 2 hours on high and 4-6 on low. The solar controller rarely keeps the pump on high for longer than 2 hours but if I leave the cover off then I need to run at high speed for longer to make up the additional heat loss.

Also, you don't "need" a variable speed pump for solar, there are many who use single and two speed pumps although it does make easier to fine tune energy efficiency. The idea is the set the variable to the lowest flow rate to support high panel efficiency and also to keep the vacuum release valve closed. But you should be ok with your current pump.
 
3-Phase is more efficient but not by much. The biggest problem is that there are very few residential pool pumps that work with 3-phase. You could put a 3-phase motor on a standard wet end but the cost would likely be prohibitive. You might as well just go with a variable speed motor since most use 3-phase motors with a single phase input drive.
 
terriolsen,
If you have 10 panels and use the "general rule of thumb" at 4GPM per panel, so you need about 40 GPM. That would be about 70-80% efficiency for the panels.
1/2 HP 2 speed (I didn't know you can get 2 speed with 1/2 HP, I thought the minimum was 3/4HP) would not get you 40 GPM because under a common head of about 50 and up, you'll be luck to get 30GPM.
I just installed the ePump 1.5HP and I can tell you that thing is quite....
But to the point,
I have my 10 panels on a 1 story roof, and i found that I must prime them and thus close the vacuum valve, at about 2700 RPM / 700W for about 3-5 minutes, I will calc the GPM later but from the curves seems like 70 GPM. Then after it is primed, i slow down the speed to its default eSaver of 1750 RPM / 200W, and the flow is about 40 GPM. I was even able to slow i down to 1300 RPM and the water was still flowing thru the solar but since the IC40 chlorine generator started to cry on low flow rate, i assume I was under 35 GPM...
Priming is a KEY, and seems that even if you have a 2 story roof, as long as you prime the panels, you could slow it down/switch to low speed in case of a 2 speed pump and it should work just fine.
Without priming, at 1750 RPM i didn't get any/minimal flow as the vacuum valve did not close...
One benefit that i can already see is that i can run my solar at 200W compared to my old one speed 1.5HP ultraflow that was yanking about 2300W. That is amazing. Even if i wanted to run it at 70 GPM, i would be at 700W....vs. 2300....
 
Laker4ever said:
1/2 HP 2 speed (I didn't know you can get 2 speed with 1/2 HP, I thought the minimum was 3/4HP) would not get you 40 GPM because under a common head of about 50 and up, you'll be luck to get 30GPM.
Click to expand...

I built my own 1/2 HP 2 speed pump and it gets over 50 GPM with solar running and 70 GPM without solar.
 
I built my own 1/2 HP 2 speed pump and it gets over 50 GPM with solar running and 70 GPM without solar.
Click to expand...
Mas985,
Can you please elaborate.
By "build your own"... I believe you mean that you combined wet end with some motor and impeller combination...
It would be interesting to know the Watts you pump pulls at your 50 GPM with solar and 70 GPM without.
It seems to me that either you have extremely low head in a form of very large pipes/filter/ short distances or there is some other magic.
Also the 50 and 70 GPM are at high speed both right?
 
My plumbing is decent but nothing out of the ordinary. 2.5" suction and 2" returns with 2" solar runs to a second story roof.

I use to have a 1 HP Northstar pump and I swapped out the impeller for a 1/2 HP Northstar and replaced the motor with a 1 HP uprated 2 speed motor. Here are the operating points:

Without Solar Full Speed: 71 GPM, 31.5' of head, ~1180 Watts
Without Solar Half Speed: 34 GPM, 8.4' of head, ~245 Watts
With Solar Full Speed: 52 GPM, 42.7' of head, ~1087 Watts

When I had the 1 HP, the operating point was:

With Solar: 68 GPM, 68' of head, ~1900 watts

So cutting the HP in half only reduces the flow rate by ~24% but power consumption by over 40%.

Most in ground full rated 1/2 HP pumps will have more than enough head for solar.
 
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