Water pump - how many watts

[thuisinthailand]

Hi everyone,

Thanks to the remarks in this topic

http://www.thaivisa.com/forum/topic/817609-water-tank-or-not/

we made our plan for the water tank installation around our house. I thought I had everything clear but then came to the question: which pump to buy? I discovered already that for a water tank (above ground) you need a constant pressure pump. I almost bought the Hitachi P350GX but then I read that for a single story house (our house actually has 2 stories, but water - kitchen, bathroom - is only downstairs) a pump with 100 or 150 watt should be enough. And that by putting a stronger one (like the Hitachi with 350 watt) we run the risk of blowing up existing pipes in the house.

Is this true? Any thought on this one? Advice on brand maybe? Maximum budget for the pump is 10K baht.

[IMHO]

How many taps will be used concurrently? 150W is very good pressure for one tap, so-so for 2, useless for 3, for example.

[thuisinthailand]

How many taps will be used concurrently? 150W is very good pressure for one tap, so-so for 2, useless for 3, for example.

I see, so if you take a shower directly after flushing the toilet and someone else is washing the dishes, pressure is gone already with a 150W... So better take the 350W after all. Thx.

[Forkinhades]

Our storage tank is in the ground and is pressurised, our house is 2 storey. We have a 300W pump. We can run the whole house without the pump!, and indeed do

[KhunBENQ]

We,have a two storey house.

Have a 250 Watt Hitachi pump without pressure tank (no good idea).

More than enough flow.

How many persons in the household? More than one bathroom?

I would not buy bigger.

If I get to buy a new pump I would buy a Mitsubishi with pressure tank.

Like this:

And I would choose a model with only 205 W.

The sister in law has such a model.

You hardly hear it working and it does not tend to pulsate.

"no good idea": the Hitachi is fairly loud and due to the missing pressure tank it goes to pulsate if you don't open the tap fully enough.

[thuisinthailand]

My Thai neighbour says that I should buy a 250W Daiwoo pump. Never heard of tgat one. He says: more then enough power for the tank and our house and saves electric. Any thoughts?

[Pib]

You don't need a constant pressure pump for an above ground tank...a constant pressure or non-constant pressure will work with a below or above ground tank.

I have a Mitsubishi WP255 pump (non-constant pressure, 250W pump) which looks like the picture in KhunBENQ's post above and an above ground tank...been using it around 7 years now. It feeds water to my two story, 3 bathroom house just fine...second story water pressure is just fine/steady....pressure to the water hoses around the yard is just fine/steady. I would say the great majority of pumps in my moobaan use a non-constant pressure pump with above ground tanks based on my field of visions when doing my dog walks and jogging around my large moobaan of approx 750 homes.

Constant pressure pumps are overrated and cost more than non-constant pressure pumps like I have. Plus they are a little more complicated and arguably more prone to problems since it runs more compared to a non-constant pressure pump with pressure tank like mine. While a non-constant pressure pump does indeed allow the pressure to vary up and down approx 3 to 5psi for all practical purposes you will be hard pressed to notice this variation...and the variation you may notice is minor.

Just because a pump has a larger model number/wattage rating does not necessarily mean it puts out more "pressure" than a model number with a lower number/wattage. Don't worry about blowing up pipes. The pressure output can still be the same but the "volume" of water a pump can supply will be different. For example, Mitsubishi model numbers WP255 (250W), WP305 (300W), WP355 (350W), and WP405 (400W) have almost identical pressure outputs (i.e., PSI/Bar) but with each sequence higher in the model number the water volume output (i.e., liters per minute) is approx 10% higher which is important if you have multiple taps using water at the same time which is probably not the norm in a house, because usually you probably only have one or two taps using water at the same time....just think when and how long any water tap (sink, commode, shower, washing machine, water hose, etc) is on during the day.

Recommend you get a pump (non constant pressure or constant pressure in the 250 to 300 watts ballpark) which has a pressure output in the 2.1 bar/30 psi to 2.8 bar/40psi output range...usually around the 200 and below model/wattage range the pressure output drops to around 1.0 to 1.9 bar range.

[StefanBBK]

We,have a two storey house.

Have a 250 Watt Hitachi pump without pressure tank (no good idea).

More than enough flow.

How many persons in the household? More than one bathroom?

I would not buy bigger.

If I get to buy a new pump I would buy a Mitsubishi with pressure tank.

Like this:

And I would choose a model with only 205 W.

The sister in law has such a model.

You hardly hear it working and it does not tend to pulsate.

"no good idea": the Hitachi is fairly loud and due to the missing pressure tank it goes to pulsate if you don't open the tap fully enough.

Two story house and use the 250W mitzubishi pump with Tank. Works great.

[plfomylo]

hello,

 

can you tell me what is the cheapest water pump that I could buy (and where) to replace this one if you think that it is broken 

 

 

 

thank you

[VocalNeal]

150Watts it is written on your pump.