Comparing Pumps with similar caudal

[metRo_]

I'm choosing a filter+pump to buy and after some research about what I need here looks like something between 7000L/h to 10000L/h would be ok. So a user suggest me this pump+filter http://www.swimpools.eu/article.php?query=28648gs|29058|zwd1007 but I was thinking to buy it here in Portugal or Spain and we it is easier to get GRE products here and I find the following three products:

1)SAND FILTER D.430 + PUMP 230W GRE. FA6070 - 386,50 €

- Ø de la cuba 430mm.
- 7.000 L/h.
- Pump power 230W – 0,31CV/HP.
- Sand ±68kg.
- 6 valve mode: lavado(clean filter), enjuague(other kind of clean the filter), filtración(filtrar), recirculación(direct from pump to pool), vaciado(from pump to waste) y cerrado(close).
2)SAND FILTER D.500 + PUMP 630W GRE. FA6080 - 435,00 €

- Ø de la cuba 500mm.
- 8.000 L/h.
- Pump power 630W – 0,86CV/HP.
- Sand ±90kg.
- 6 valve mode: lavado(clean filter), enjuague(other kind of clean the filter), filtración(filtrar), recirculación(direct from pump to pool), vaciado(from pump to waste) y cerrado(close).

3)SAND FILTER D.500 + PUMP 550W 8m3/h Gre - 321,80 €

- Ø de la cuba 500mm.
- 8.000 L/h.
- Pump power 550W – 0,75CV/HP.
- Sand ±85kg.
- 5 valve mode: lavado(clean filter), enjuague(other kind of clean the filter), filtración(filtrar), vaciado(from pump to waste) y cerrado(close).

Between 2 and 3 is easier to choose, they have the same system flow, the number 3 is more efficient, is cheaper but doesn'g have circulation mode (by the way, do I really need it?)

BUT the number 1 have all the things, use less than 50% power compared to 2 and 3, the cost is between the two and only have less 1000l/h. How the number one is so efficient? Isn't power and system flow proportional?

 

[jblizzle]

Likely the power numbers are just wrong like they are in the US also.
You will use roughly the same amount of power to move the same amount of water.

To add another wrinkle, 2-speed pump are usually recommended because you can save a lot of money on electricity by running on low most of the time and only on high for backwashing, vacuuming.

 

[metRo_]

If we estimate a 4 hour day runtime we got 4h*0.550W*0.16€*30=10,56€

can I save that much with a 2 speed pump that willing buy it? I didn't find any 2 speed pump on that price range

 

[jblizzle]

The 2-speed will cost more ... but should be able to save you at least 50% of the electrical costs pretty easily.

 

[metRo_]

When do you use low speed and when do you use high speed?

 

[jblizzle]

Always use low speed ... except when you need high speed
You need high for backwashing the filter or maybe vacuuming.

 

[metRo_]

argghhh now I'm undecided again lol

I think I'll go for a 1 speed, first because it is my first pool, then because my pool is very small and last because the using your pump as comparison I'll need at least 6 years of 50% savings to pay the diference.

So about my first question I should look at system flow and not at the power value if it doesn't make sense, right?
And about the valve mode that send the water directly from pump to pool (recircluation), is it important?

 

[cowboycasey]

I vote for number 2, you will use re-circulation when you have a bad algae outbreak and you have to go to work...

 

[metRo_]

I vote for number 2, you will use re-circulation when you have a bad algae outbreak and you have to go to work...

Can't I add a T between pump and filter?
PUMP --x-- FILTER
...........|
........POOL

 

[jblizzle]

That would be an odd setup, but possible I suppose ... if you go to the same pool return, then you would need a way to prevent back pressurization into the pump.

Those 3 being my only choices, I would get #1 given your small pool

 

[metRo_]

That would be an odd setup, but possible I suppose ... if you go to the same pool return, then you would need a way to prevent back pressurization into the pump.

Those 3 being my only choices, I would get #1 given your small pool

The portuguese distrbutor from GRE told me that the low pirces of the new pump+filter (the #3 one) is to get the products on the market. There is also a new version similar to #1 Monobloc de filtracin piscinas - Gre - Piscinas - Pool - Piscine - Schwimmbecken - Zwembaden
only for 230€ but has a lower sand deposit.

- Ø 368cm
- system flow 6,5M3/h
- pump power 450W
- sand ±35kg
- 7 valve mode: lavado, enjuague, filtración, circulación, vaciado, cerrado e ivernaje

 

[metRo_]

Hello again,
Last year I wasn't able to finish the pool however during the last months I had worked on it and now I'll finally buy the pump+filter

I suppose that from last year there is nothing new on pump+filter market so I'll decide between the options here.

I had a vote for #1 and #2, anyone can help me decide between them? My only concern not going with #1 is that some people said more power is good for clean the pool.

What are the diferences between the size of the sand filter?

 

[mas985]

I believe in Europe, they use watts as a motor output rating were as we in the US use HP (shaft power in watts = HP * 0.75). So to find the input power required to drive the motor, you need to take the motor efficiency into account. Motors that small will probably have an efficiency of around 65%. So if the pump rating is 450W, it is likely to draw around 700 watts which is still pretty small but if you notice so is the flow rate (~35 GPM).

 

[metRo_]

I believe in Europe, they use watts as a motor output rating were as we in the US use HP (shaft power in watts = HP * 0.75). So to find the input power required to drive the motor, you need to take the motor efficiency into account. Motors that small will probably have an efficiency of around 65%. So if the pump rating is 450W, it is likely to draw around 700 watts which is still pretty small but if you notice so is the flow rate (~35 GPM).

Looking at pump power on the first post do you think some show the power at input and others at output? The flow is very identical between them...

For a small pool like mine will the sand deposit size make too much different?

 

[mas985]

I believe they are all showing the motor rating for power delivered which is at the motor shaft output. This is what most if not all manufactures do.

Do you have a link to a web site that is selling these? The link you posted earlier does not seem to work.

 

[metRo_]

I believe they are all showing the motor rating for power delivered which is at the motor shaft output. This is what most if not all manufactures do.

Do you have a link to a web site that is selling these? The link you posted earlier does not seem to work.

I updated the links and here is the pump+filter list FILTRATION KITS - Pools Filtration - Gre - Piscinas - Pool - Piscine - Schwimmbecken - Zwembaden

 

[mas985]

So I am pretty sure, the wattage shown as a specification is directly related to the label HP of the pump. However, that does not take into account the service factor of the motor nor efficiency although for most AG, pool equipment the service factor is close 1. So the input power of the motor is likely more than 50% higher than the wattage rating shown in the specifications.

 

[metRo_]

So I am pretty sure, the wattage shown as a specification is directly related to the label HP of the pump. However, that does not take into account the service factor of the motor nor efficiency although for most AG, pool equipment the service factor is close 1. So the input power of the motor is likely more than 50% higher than the wattage rating shown in the specifications.

Based on my pool which one would you buy?
I can't decide :s I don't want to buy something overrated however I don't else buy something that doesn't have power for clean the pool :s

 

[pooldv]

I vote for #1.

 

[mas985]

I think any of them would work fine. However, the advantage of the larger filters is there is more time between backwash's. The advantage of the smaller system is less energy use. You need to decide what is more important to you.