Pool pump sizing

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olive
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Pool pump sizing

Postby olive » Fri Jul 06, 2018 12:51 pm

Paging T d A! Or anyone.

When our pool was put in it came in a fibreglass cube with lid with pump, control box, manifolds, piping and of course the filter itself.

When we sat down with the installer prior to work he sort of hesitated when he said it would have a 3/4 horsepower espa pump. We asked would it be better with a one hp. That might have been lost in translation and we ended up with one hp. My thought at the time was it would circulate the water in a shorter time and wouldnt cost much more at the time. Pump prices seem to be about the same price regardless of power.

We have had the pump repaired twice . New capacitor and bearing.it has started doing the same thing again. Switch on and buzzes with no turning.

So I am thinking 13 years of service maybe time for a new and quieter pump to boot. Question is ... Is the filter sized to the pump? Maybe if I buy new I ought to go to 3/4 hp. Pool is approx 75 cu m water. Anyone know about this stuff?

TorreDelAguila
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Re: Pool pump sizing

Postby TorreDelAguila » Fri Jul 06, 2018 2:27 pm

Hi there, Olive

Espa pumps have a good reputation for reliability.

Starting capacitors can and do give up, and what you describe (buzz, but not running) is a sure sign that the capacitor (essential for starting) is likely duff. Cheap enough to replace, but be sure to get exactly the right value (will read something line 14uF, 400/450V). The required value of the capacitor is usually marked on the motor rating plate. For a normal 230v domestic supply, you should be using a 400V+ capacitor, to cope with the surge/spike that motor starting involves.

This is a shot of our pool pump room:
DSCF3395r.jpg

The pump is an Espa, model Silen 75M: 1.2kW (1200W), 2800rpm, 150-300 lit/min (9-18 m3/hr)
It's 17 years old, and on its second starting capacitor.
Bearings, etc all original.
When run continuously (eg for most of a day, to do a big clean-up), the metal finned body of the pump and the plastic pump casing get mildly warm, but never hot. It has a good fan built in.

Your pool is larger than ours at 75m3 - ours is 64m3 - so I wouldn't expect to see a pump smaller than ours, and certainly not a small as 3/4HP (= roughly 550W). Even our standard Espa domestic water pump is 700W (1HP)...
espa pump_2.jpg
espa pump_2.jpg (12.22 KiB) Viewed 897 times


So, I'd be suggesting you go for a bigger motored pump, 1200W or so. This would probably enjoy a longer life, because it wouldn't be working so hard.

Your question, Is the filter sized to the pump? Answer is yes. What you should obtain is a pump with the larger motor, and this comes complete with the plastic pump body and its rotors inside, plus the attached vertical filter assembly/basket. This will attach to your existing pipework, 'pump input' and 'pump output'. Couplings are usually standard type.

If you eventually remove this lump (motor+pump+filter), a good supplier should simply be able to offer you another unit which will fit, but with a larger driving motor. Might be a good idea to take your old unit (m+p+f) to the supplier, when you obtain the new one, to check they match up. Hopefully, you'll have enough space in the hole-in-the-ground for the new and larger motor.

Hope helpful.
Last edited by TorreDelAguila on Fri Jul 06, 2018 9:37 pm, edited 1 time in total.
Chris

Torrox_campo
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Re: Pool pump sizing

Postby Torrox_campo » Fri Jul 06, 2018 3:01 pm

I would look at the flow rate of the old pump for example if the flow rate is 15 cubic metres per hour etc. So to turn the whole pool volume of water once you will need the pump to run by 75÷15 hours which is 4 hours.
If you have been running, say 2 hours per day with the pump flow rate of 15 cubic metres per hour with good result then it means that you only need to shift 30 metres of water per day. A more powerful pump with a flow rate of 30 cubic metres/ hour will let you run the pool pump 1 hour per day with similar result.
In general pumps are defined by the flow rate and the "head" ie. how high the pump has to deliver relative to the pump posistion . As your pump arrangement is similar height to the pool you don't need to worry about the "head" but concentrate on the flow rate the pump can deliver. Depending how long you want the new pump to run you can choose one that suits your need.

El Cid
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Re: Pool pump sizing

Postby El Cid » Fri Jul 06, 2018 4:59 pm

We have an Espa Silen 150M which is 1.5HP. The pool is about 100M3 - don't know exactly as it is a complicated shape - all curves.

I never need to run it for more than 2 hours as the pool is not heavily used. It's the second one in 15 years. First one lasted 10 years.

Sid

olive
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Re: Pool pump sizing

Postby olive » Sat Jul 07, 2018 7:14 pm

Thanks for the advice. i am in the UK at the moment so cannot check the size of pump fitted. It is the same shape/style as the one in your photo TdA. I need to do something on Thursday as it hasnt worked for a few days now.

My question about sizing wasnt pipe fittings wise but relating to the filter. Can a pump be too powerful for the sand and reduce the filtering efficiency or some other detrimental effect?

El Cid
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Re: Pool pump sizing

Postby El Cid » Sat Jul 07, 2018 8:41 pm

I doubt that the filter size makes much difference unless it is wildly out. A bigger pump will just push the water through quicker and more importantly give better suction on the vacuum side making cleaning the pool easier. You need to remember that if you have a clean pool with no unfortunate debris in it and is clear then the filter and the circulation is actually pointless, passing clean water through a filter achieves nothing apart from increasing your electricity bill! Sanitation is achieved entirely by the chemicals in the pool, not by the filtration.

Sid

TorreDelAguila
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Re: Pool pump sizing

Postby TorreDelAguila » Sat Jul 07, 2018 9:28 pm

Agree with Sid on all of that.
Chris

olive
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Re: Pool pump sizing

Postby olive » Thu Jul 12, 2018 4:24 pm

Had a look at the pump. It is an ESPA Silen 100M single phase. I managed to get it to run once today but that was it.


Torn between like for like or the next one up the 125M. The flow rate difference isn't that much 12,800 as opposed to 14,000 l/hour. Price difference , unusually , isn't that much either.


These folk seem good on price https://www.piscinayspa.com/accesorios- ... spa-silen/ but you cannot beat taking the old one along to compare offsets, outlet position and pipe diameters. I think I will try Proinco in Antequera..

TorreDelAguila
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Re: Pool pump sizing

Postby TorreDelAguila » Thu Jul 12, 2018 5:48 pm

I use Proinco down here in Velez-Malaga. Find them really good.
Just avoid the pool shops - really expensive!

Either of those models should do - just make sure they're physically the right size, and you have room enough. Good idea to take the old one.

The capacitor on this type of motor is mainly needed for starting, so if it has gone west, the pump may or may not start when switched on, but will usually start up ok if you give it a helping twirl . . . not easy on a pool pump!
The capacitor also 'corrects the power factor'*, ensuring that the pump runs as powerfully and efficiently as possible.

* Please don't ask for an explanation of that, it doesn't make good bedtime reading.
Chris

Torrox_campo
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Re: Pool pump sizing

Postby Torrox_campo » Thu Jul 12, 2018 9:56 pm

Sound likes capacitor problem as TorreDelAguila mentioned above, when I came back to mi casa last January my pool pump stopped working, thinking of replacement but after checking it was the capacitor fault. I changed the capacitor, cost about €10, it works fine ever since. Worth looking at the capacitor by swapping to a new capacitor! My pump is certainly older than 13 year old.

olive
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Re: Pool pump sizing

Postby olive » Tue Jul 17, 2018 6:06 pm

Update. Got a like for like replacement from Proinco. Bit more than from mail order. Happy enough though. Inlet is larger than old one but it comes with options to change with a bit of work. I thought it was a bit mean to not have mains cable supplied. Anyway it is up and working. Thanks for help.

Lot quieter than old one and I like the process for removing filter with supplied tool. Old one was quite hard work

TorreDelAguila
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Re: Pool pump sizing

Postby TorreDelAguila » Tue Jul 17, 2018 8:13 pm

Glad it's all in and working - well done, you! :thumbup:
Yes, filter (basket) design has improved over the old style.
Chris


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