Is a pool pump speed controller necessary ?

Pool pumps, pool filters and the plumbing of
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Teapot
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Re: Is a pool pump speed controller necessary ?

Postby Teapot » Wed 18 Oct, 2017 09:53

Hsiao, we need to know the size of your pool, the diameter of the plumbing, the size of your filter (dia), type of filter and length of plumbing run approx. You may want to add these details to your profile.
I started out varying the speed for different occasions (night and daytime) but like a lot of these features I don't use them now, just the increased speed for backwashing. I run around 69 watts so you can't go much lower.


Hsiao Chang
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My Pool: 110m3; 1.5hp pump Qmax: 350l/min Hmax:14m ; sand filter dia: 450mm,33kw heat pump, piping : 50mm

Re: Is a pool pump speed controller necessary ?

Postby Hsiao Chang » Wed 18 Oct, 2017 20:08

Denniswiseman wrote:What is the size of your pool (gallons/Llitres)
The controller sounds excellent being able to time at different speeds
I went from a 1hp to a .5hp because my pump was pushing to much water through my sand filter to filter properly
My pool is 10k UK gallons 45000 litres


It is a 110 CBM pool, 110k liters. yes, it sounds good as it offers 4 timers, though i don't think it's necessary to set so many as 4 and the
different of electricity rate vary little here during day or night , but the idea of running at a lower speed could cut the bill. but if i set the speed too low
i might have a problem with heater , do i understand this correctly please ?
Denniswiseman
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Re: Is a pool pump speed controller necessary ?

Postby Denniswiseman » Thu 19 Oct, 2017 02:35

Yes you are correct
Running at a slower speed will reduce your running costs substantally
You would have to adjust your speed by trial and error to find the minimum flow rate through your heater for it to operate
The same goes for a SWCG
I would think that you could run on a higher speed for cleaning / skimming / mixing chems then reduce to what lower speed operates your heater
There is no set rule for water turnover, whatever cleans your water
Teapot
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Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: Is a pool pump speed controller necessary ?

Postby Teapot » Thu 19 Oct, 2017 03:34

Hsiao, we need to know the diameter of the plumbing, the size of your filter (dia), type of filter and length of plumbing run approx. You may want to add these details to your profile.
The correct flow for your heater will be spec'd in the manual, often around 5m3/h. Is your heater plumbed on a bypass loop so you can adjust it?
You should get a flow meter to check the best flow to turn over your water. Gage & Bidwell's law of dilution gives us some expectations on how much water actually makes it through the filter. 1st turnover 63%, 2nd 86%, 3rd 95%, 4th 98%, 5th 99% of the water filtered. There are alternatives but they are all pretty close to one another. Personally I am happy with 4 turnovers per day and that fits nicely with the energy usage.
Hsiao Chang
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Joined: Thu 12 Oct, 2017 20:09
My Pool: 110m3; 1.5hp pump Qmax: 350l/min Hmax:14m ; sand filter dia: 450mm,33kw heat pump, piping : 50mm

Re: Is a pool pump speed controller necessary ?

Postby Hsiao Chang » Thu 19 Oct, 2017 20:45

Denniswiseman wrote:Yes you are correct
Running at a slower speed will reduce your running costs substantally
You would have to adjust your speed by trial and error to find the minimum flow rate through your heater for it to operate
The same goes for a SWCG
I would think that you could run on a higher speed for cleaning / skimming / mixing chems then reduce to what lower speed operates your heater
There is no set rule for water turnover, whatever cleans your water


Thank you Dennis, I think I understand things better now with your info. and instructions. the lowest RPM the pump speed controller can set is 1200 RPM,
it's even a lot less than 50% of its max. speed, 2900 RPM, I doubt if a pump would ever go that low because cleaning /skimming/ mix chems are
basics of a pool system which you can not skip.... or this could be something gimmicky, it 'sounds' great ,but not really practical in reality .
Hsiao Chang
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Joined: Thu 12 Oct, 2017 20:09
My Pool: 110m3; 1.5hp pump Qmax: 350l/min Hmax:14m ; sand filter dia: 450mm,33kw heat pump, piping : 50mm

Re: Is a pool pump speed controller necessary ?

Postby Hsiao Chang » Thu 19 Oct, 2017 20:56

Teapot wrote:Hsiao, we need to know the diameter of the plumbing, the size of your filter (dia), type of filter and length of plumbing run approx. You may want to add these details to your profile.
The correct flow for your heater will be spec'd in the manual, often around 5m3/h. Is your heater plumbed on a bypass loop so you can adjust it?
You should get a flow meter to check the best flow to turn over your water. Gage & Bidwell's law of dilution gives us some expectations on how much water actually makes it through the filter. 1st turnover 63%, 2nd 86%, 3rd 95%, 4th 98%, 5th 99% of the water filtered. There are alternatives but they are all pretty close to one another. Personally I am happy with 4 turnovers per day and that fits nicely with the energy usage.

Hi Teapot, thanks for your input, sorry i didnt realize this thread has come to 2nd page.i will update my profile after this reply.
Pool: 110 CBM
Pump: 1.5hp Qmax: 350l/min; Hmax: 14m
Connection: 50mm
Sand filter: 450mm
heatpump: 33kw output @26C/26C
Teapot
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Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: Is a pool pump speed controller necessary ?

Postby Teapot » Fri 20 Oct, 2017 02:39

Hi Hsiao, Thanks for the information. Yes you can save quite a bit by slowing down your pump. If I were building your setup you would have two 450mm filters for 110 CBM which would filter better and drastically cut your headloss.
More later as I have to go to work.
Denniswiseman
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Re: Is a pool pump speed controller necessary ?

Postby Denniswiseman » Fri 20 Oct, 2017 02:58

I have a 27kw heat pump and my minimum flow rate is 9 cubic metres hour
My .5hp pump gives me a flow rate of 10.8 cubic metres hour
Your pump has a flow rate of 21 cubic metres hour so I would expect you should be able to reduce your speed quiet a bit without affecting your heat pump check your minimum flow for your heat pump to work bearing in mind that you can always turn it up
Generally speaking you should match your pump to your filter (check your filter flow rate) as to great a flow doesn't filter as well because it is forcing the water through and not filtering
Slowing the flow will help filtering
Teapot
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Posts: 1337
Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: Is a pool pump speed controller necessary ?

Postby Teapot » Fri 20 Oct, 2017 12:56

The flow rate stated on the pump is at zero head, on a pool setup with a small sand filter like Hsiao's, I doubt if it's actually flowing any more than 10m3 or a bit less. Forget what manufacturers say they are just in competition with other manufacturers.
This week I removed a 2HP pump from a small pool with a 600mm (24") sand filter and that was only flowing at 10.3m3/hr. That's why I have recommended a flow meter, the only real way of seeing whats actually happening and vital when you go to multi speed pumps with low energy.
Hsiao, what does your pressure gauge read?
Hsiao Chang
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My Pool: 110m3; 1.5hp pump Qmax: 350l/min Hmax:14m ; sand filter dia: 450mm,33kw heat pump, piping : 50mm

Re: Is a pool pump speed controller necessary ?

Postby Hsiao Chang » Sun 22 Oct, 2017 22:03

Thanks you Dennis and Teapot for your information.
The pressure gauge reads 12 PSI. is there such a thing as an appropriate pressure reading given my pool setup please ?
why would you recommend 2 450mm filters for a 110 pool please ?
Denniswiseman
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Location: United Kingdom

Re: Is a pool pump speed controller necessary ?

Postby Denniswiseman » Mon 23 Oct, 2017 03:49

Hsiao Chang wrote:Thanks you Dennis and Teapot for your information.
The pressure gauge reads 12 PSI. is there such a thing as an appropriate pressure reading given my pool setup please ?
why would you recommend 2 450mm filters for a 110 pool please ?

12 psi is OK for a clean system, however when the pressure rises 20 to 25% higher it's time to backwash
The bigger the filter is better
Normally you match a filter to the pump so that you aren't trying to push to much water through a filter which doesn't filter properly. Check your filter recommended flow rate and the flow rate of the pump
Apart from reducing your electricity bill, pump speed will also reduce your flow rate
It's a myth that you need "X" amount of water turnover, all you need is enough to clean, skim, run SWCG and mix chemicals
Teapot
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Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: Is a pool pump speed controller necessary ?

Postby Teapot » Mon 23 Oct, 2017 04:36

Hi Hsiao,
1st answer: To run efficiently the lowest possible positive pressure is the best, pressure above that is just wasted energy through friction. However your pump would most likely cavitate unless setup carefully. Some pump controllers run a flat out cycle to achieve pump prime then onto a reduce speed as set by the operator. Others allow you to set the start up speed so you can slow start to lessen cavitation issues.

2nd answer: I didn't ask how many bathers use your pool and if it is indoor or outdoor? I recommend two filters for that size pool based on the maximum flow of the filter and your likely pool water turnover rate with the surface area of the filter before it clogs. Others have one big filter but they generally take up too much room and it's cheaper to add another filter of the same size you have now than buying a larger filter. Backwashing is also easier if you have isolating valves for each filter and variable speed pump.

By example, I have a customer with the same size outdoor pool as you and around 16 bathers at any one time. This pool uses a big Triton TR140 filter and my very special setup. Technically the pool needs to turnover every 4.5 hours and we can do this on 500 watts. However slightly slower filtration produces better filtration results and the customer actually runs it on 126 watts which gives him a flow 15m3/h at a filter pressure of 0.5 PSI.
This is a massive saving on the original 2.2kw pump which used around 2300 watts.

I hope that helps, it takes time on forums to get the whole picture, It's easier when I am with a customer and can asses the whole setup, nearly always beginning with the flow meter. I have done flow tests on lots of pools and record the data and customers are usually surprised at their results not being anywhere near what they thought or the pump plate says. the pump performance curve which normally comes with the pump doesn't take into account the filter or the plumbing and they have a massive effect on the energy usage and performance.
Hsiao Chang
Pool Enthusiast
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Posts: 24
Joined: Thu 12 Oct, 2017 20:09
My Pool: 110m3; 1.5hp pump Qmax: 350l/min Hmax:14m ; sand filter dia: 450mm,33kw heat pump, piping : 50mm

Re: Is a pool pump speed controller necessary ?

Postby Hsiao Chang » Tue 24 Oct, 2017 01:14

Thank you for your advice Dennis, so i will have regular check on the pressure .

" Normally you match a filter to the pump so that you aren't trying to push to much water through a filter which doesn't filter properly..."

my understanding to this is , when you are setting up a pool, you decide on size of a pump first, then a filter.

Factors to consider when sizing a pump:
a).minimum flow rate (decided by pool volume/ turnover ) ;
b). total head ( which is the total friction of piping system, depends on length of pipes, diameter, number of turns etc ).

Factors to consider when sizing a filter:
refer to flow rate for the pump, but the bigger , the better.
Hsiao Chang
Pool Enthusiast
Pool Enthusiast
Posts: 24
Joined: Thu 12 Oct, 2017 20:09
My Pool: 110m3; 1.5hp pump Qmax: 350l/min Hmax:14m ; sand filter dia: 450mm,33kw heat pump, piping : 50mm

Re: Is a pool pump speed controller necessary ?

Postby Hsiao Chang » Tue 24 Oct, 2017 01:27

Hi Teapot ,
To answer your question :basically there are 6 ppl using the pool, some weekends around 10 ( not quite often ).

your customer's case : 110 M3 pool, turnover 4.5hr 500w , with same size pool, mine uses a 1.5hp pump, that's quite an oversized pump , am i correct ???
I suppose I do need a pump speed controller then ?

it's a little frustrating that i spent more money on a big pump, and in order to bring down cost of this big pump,
i need to spend more on a speed controller... is there a simple way or a general rule of thumbs for ppl properly sizing their pump rather than wasting money , please ?
Denniswiseman
Pool Industry Leader
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Posts: 2592
Joined: Tue 06 Sep, 2011 05:48
My Pool: 10k inground fibreglass, Telescopic Cover, Hayward Powerline pump, Quality filter with glass media, 27kw output heat pump, K-2006C test kit
Location: United Kingdom

Re: Is a pool pump speed controller necessary ?

Postby Denniswiseman » Tue 24 Oct, 2017 01:50

Hsiao Chang wrote:Thank you for your advice Dennis, so i will have regular check on the pressure .

" Normally you match a filter to the pump so that you aren't trying to push to much water through a filter which doesn't filter properly..."

my understanding to this is , when you are setting up a pool, you decide on size of a pump first, then a filter.

Factors to consider when sizing a pump:
a).minimum flow rate (decided by pool volume/ turnover ) ;
b). total head ( which is the total friction of piping system, depends on length of pipes, diameter, number of turns etc ).

Factors to consider when sizing a filter:
refer to flow rate for the pump, but the bigger , the better.

Yes you have the right idea

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