Is a pool pump speed controller necessary ?

Pool pumps, pool filters and the plumbing of
swimming pools. Sand filters, cartridge filters,
fabric filters and alternative filter media.
Teapot
Swimming Pool Wizard
Swimming Pool Wizard
Posts: 90
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 » Wed 22 Nov, 2017 07:41

Denniswiseman wrote:Hi Hsiao

That is running at full speed it's 3/4 kw down to a light bulb


Hsiao, whilst you have a power meter fitted, as I have said all the way through you need a flow meter to tell you exactly what the pump is pushing through the system.
Pumps are made with an impeller of the right size and shape to operate at the given RPM. yes you can vary that to a point but too slow and they become inefficient and the flow through the system will be too low to achieve clearing the water. With low batherload pools you can get away with a lot but these are schoolboy errors to assume you can just wind down the pump.
I have had people do just that and they lost control of their pool and had to turn the system back up. Guessing only, you could wind down the RPM by 33%-about 50% of the power safely but with a flow meter you get the real data and you will see when using low power how quickly the flow drops when the filter begins to get dirty, along time before the gauge shows an increase in pressure.

Pool equipment was never designed to be efficient so if you tinker you can end up worse off. When I setup a system the most important part is to monitor the flow at given pump RPM and from that we can setup what works.

I have spent my time designing super efficient pool systems and I know what will work and what won't. My pool runs at 60-69 watts per hour at the proper flow rate to turn over the pool. I am working on a new filter that should improve on that even more and actually backwash properly.


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 » Wed 22 Nov, 2017 21:28

Hi John, there will be a flow meter installed for me, i will adjust the speed accordingly to find the right flow. according to your experience, may i ask how many turnovers do you think appropriate per day for a pool with low batherload please?
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 » Wed 22 Nov, 2017 21:41

Denniswiseman wrote:Hi Hsiao
Can you post details and costings for others as that seems excellant and can offer alternatives
That is running at full speed it's 3/4 kw down to a light bulb


Hi Dennis, there was a technical guy who explained me an affinity low, which i googled afterwards, yes, only turning down the speed a little bit, power consumption
drops a lot. that's why when a speed reduced by 50%, power dropped by 80%. and for proper filtration, you dont need a backwash speed.
I bought it through a friend, who knows the manufacturer, so i got a better retail price, 300 USD. but as John put, you will need to have an idea about the actual flow running
through the system, so it's not necessarily you are saving 80%.
Teapot
Swimming Pool Wizard
Swimming Pool Wizard
Posts: 90
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 23 Nov, 2017 09:18

Hsiao Chang wrote:Hi John, there will be a flow meter installed for me, i will adjust the speed accordingly to find the right flow. according to your experience, may i ask how many turnovers do you think appropriate per day for a pool with low batherload please?

Thank you Hsiao, nice to be listened to.
You need to take account of the min flow your heater can have.

From my earlier post I mentioned Gage & Bidwell who mathematically calculated the dilution figure and therefore the filtration level for a given number of passes through a filter.
Teapot wrote: 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.

Is the pool outdoors or indoors?
If it's out doors uncovered then the skimmers only work when the pump is running. So when it's not running dirt enters, sinks to the bottom and requires manual removal.
If you run your pump 24hrs per day then the dirt will get collected and water filtered leading to much cleaner water and less chlorine usage. We would all do this if it were cheap enough but we don't because of the expense, you are now in a different league where it might not cost anymore to run for 24 hours. Indoors you may well benefit from less pump run time.

110m3 turned over 4 times like I do, means a flow of 18.33 m3/hour and that is impossible through your filter. Turned over 3 times, means a flow of 13.73m3/h still impossible through your filter. Turned 2 times, means a flow of 9.16m3/h might just be possible through your filter. Hopefully you see why I said add a second filter?
So outdoors or indoors is very important, covered or uncovered.

I see a lot of pools, I have customers, not all take notice of me. One in particular turns over his pool just once a day, he uses more chlorine but it's swimable, not as clear as mine (1.2 NTU's) closer to 9NTU's, Another pool I converted was 12NTU's when I first saw it and that was hazy but in those days the owners knew no different.
Hope that helps.

Dennis, in our country the units are about £349, sorry I have actually misplaced my price sheet for the minute.
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 » Thu 23 Nov, 2017 21:34

Hi John, that's what i am here for, to listen to professionals as i honestly have no idea about the pool system. always grateful for the things you and Dennis told me.
I remember you saying my pump is oversized but filter undersized, my understanding is, because of this, i need a filter to better match flow of the pump can offer, hence 2x450mm filter recommended, did i get this right please ?
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 » Thu 23 Nov, 2017 21:36

Denniswiseman wrote:Hi Hsiao
Can you post details and costings for others as that seems excellant and can offer alternatives
That is running at full speed it's 3/4 kw down to a light bulb



Hi Dennis, I would suggest you get one of this speed controller too :-).
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 » Thu 23 Nov, 2017 21:42

" We all have a duty to lower our Co2 output, the oceans are becoming more acidic because of Co2 and it's so unnecessary."

----- Hi John, remember this was what you said to me/us, i watched a BBC documentary "chasing coral" , says about CO2 impact on oceans and corals. i recommended to my co workers, hopefully more and more ppl will have the awareness of protecting environment.
Teapot
Swimming Pool Wizard
Swimming Pool Wizard
Posts: 90
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 24 Nov, 2017 05:15

Hsiao Chang wrote:Hi John, that's what i am here for, to listen to professionals as i honestly have no idea about the pool system. always grateful for the things you and Dennis told me.
I remember you saying my pump is oversized but filter undersized, my understanding is, because of this, i need a filter to better match flow of the pump can offer, hence 2x450mm filter recommended, did i get this right please ?

Hi Hsiao, Yes that's correct, I now usually fit 2 filters rather than one large one as they take up less space and easier to backwash as I fit slide valves to each inlet and outlet so I can backwash one at a time/service one at a time.

Please let me have your data when you get the flow meter fitted (pump flow vs gauge pressure, rpm and watts) as it helps me build a database. You may need to get a lower reading pressure gauge for normal running.
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 » Wed 29 Nov, 2017 00:11

Hi John, i am currently working very far away from home, so i will need sometime before i can send you the data, please bear with me.

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