Advice on Buying a Water Pump for a Family Home

[kitjohnson]

I and my wife are building a two-storey house with four bedrooms and four bathrooms, and I'm looking for some advice about getting a pump, which will be placed right next to a 900 litre water tank, which will itself be fed from the Bangkok mains water supply.

 

We expect only to have two showers in use at any one time. One of these will be a rain shower, which will use quite a lot of litres/minute I expect.

 

All of the bathrooms are arranged around a central area of the house; the water pump will be near this center, and so the horizontal distance that the water needs to travel will about six metres maximum. The vertical height it needs to travel is to the second floor (4.4 metres) plus whatever the height of the shower is. This seems a really small amount of distance for the water to travel from the pump.

 

We went to get a pump yesterday. The sales staff at Boonthavorn say recommend Grundfos pumps, saying that their customers very rarely have a bad word to say about these pumps. Our architect had a similar opinion. But all of the Grundfos pumps are 500 watts or more. The one we are interested in looks great; it has an included 6 litre water tank which is pressurised, meaning that the pump doesn't need to turn on every time we turn on a tap to wash our hands. It waits until the 6 litre tank is run out before turning on again, and then it turns on long enough to get that tank full. This seems like sound design, but I couldn't see it with any of the other tanks in the store (mostly Mitsubishi).

 

It really looks like an awesome pump, but I just wondered is it possible that this pump would be over-powered? When looking at the Mitsubishi sales materials, an appropriate sized pump for our needs, given the situation I described above, would be about 250 watts. Would getting a 500 watt pump likely cause any issues except possibly an over-sized hole in my wallet? (The Grundfos pump we liked would be about 19,000 baht.)

[Kwasaki]

Whatever pump people have on here suits there purpose ours is a Hitachi it suits our two story house with washing machine on, toilets flushing and showering all at the same time. 

[juehoe]

Do have good (strong) piping installed? Then the pressure (3.5 bar) should not be a problem.

Modern pumps use now inverter technology with constant pressure and lower energy consumption.

I recommend using a pump with a power reserve. The 500 W should be enough, 750 W (with inverter technology) is better.



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[juehoe]

Grundfos is a very good brand. We use 3 of their pumps for the water supply of our project.


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[bankruatsteve]

Grundfos is the defacto premium of pumps and 500W would be more than you really need, BUT it would be a Grundfos.  An Hitachi 250 GX series would also handle your needs at about 6000 Baht.

[juehoe]

I saw that Hitachi has inverter pumps, but I have no experience with this brand, except the fridge which is very good.


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[bankruatsteve]

As a born again inverter proponent, I think they are great for things that run most of the time.  But, a water pump - at least for home use - only runs when needed.  So, I don't really get the logic that inverter would be good for that purpose.  Whatever.

[KhunBENQ]

 

35 minutes ago, bankruatsteve said:

Grundfos is the defacto premium of pumps and 500W would be more than you really need, BUT it would be a Grundfos.  An Hitachi 250 GX series would also handle your needs at about 6000 Baht.

Absolutely!

500 W is much too strong for a two story family house.

And no need to fork out 5 digit sums for Grundfos.

Sure, Grundfos is top of the list and has its value set e.g. for well pumps (submersible pumps).

But really no need to throw that much money after a house water pump as described in your setting.

We have a Mitsubishi 255 Watt pump (1 inch outlet) with pressure tank.

Works flawlessly since years, plenty of pressure in upper floor.

I read that Hitachi is superior due to overheat or dry run protection? Not sure.

And that the salesman recommends Grundfos should not be a surprise?

 

[CGW]

2 hours ago, bankruatsteve said:

As a born again inverter proponent, I think they are great for things that run most of the time.  But, a water pump - at least for home use - only runs when needed.  So, I don't really get the logic that inverter would be good for that purpose.  Whatever.

We have a couple of Hitachi Inverter water pumps, the inverter works well on water system as the pump will run constant at a low speed if using sprinkler in garden or just running small amount of water from a tap, its not full on then off again, which probably saves very little money and at the end of the day.................. ? if the pump breaks down your going to replace it, there not a lot of money given the importance....

[kitjohnson]

I'm really grateful for the replies here. My conclusion is that the Grundfos one would be great, but is overkill. The downside to this is really just paying more than we need to.

 

I'll get back to the shop and have a look at the Mitsubishi ones, around 250 watts. One advantage of the Mitsubishi ones is that they have a plastic cover. Given that this will be living under cover but nevertheless outdoors for its whole life, the plastic cover will make it a whole lot easier to keep clean.

 

Again, I really appreciate the replies.

[David B in Thailand]

Consider some ant line poison to put UNDER that cover near your pressure switch. Ants have been known to eat and harm pressure switches on any brand of water pump with a pressure switch. Ask in advance about WHO will carry out any warranty repairs on your Mitsubishi water pump | Hitachi Water Pump | Grundfos  Water pump in Thailand at your home.  

[lopburi3]

Grundfos is not overkill IMO and is the best choice as long as your pipes are up to the higher 3.5-4 bar pressure they normally operate at.  In addition they are very quiet (which can not be said for most water pumps).  Believe they are worth the cost (and have been using for several decades).  Most pumps sold here are made for direct pumping from wells and never maintain enough pressure to provide good water flow (have been using pumps here in Bangkok for more than 40 years).  If you have room would suggest larger storage tank or connecting two together to provide for any periods of outage (this also allows helps get rid of excess chlorine).  

[CGW]

^Agree, work it out on cost per day over the time period of useage, it will be less than 1 baht a day! has to be worth it for something you can't live without!

[Crossy]

I'm another Grundfos advocate. Ours (750W) now 6 years old, the only "failure" was ants in the pressure switch, a reasonably easy DIY fix and it won't happen again, ant powder used during re-assembly after cleaning.

 

We get got ants in all sorts of electrical gear, naphthalene (moth) balls discourage them and last ages in a sealed environment.

 

Even when right next to the pump you can barely tell it's running and the flow will work two showers and the washing machine.

 

 

[kitjohnson]

Now the praise for Grundfos pours in, and my mind begins to be swayed.

[wayned]

I'll third the Grundfos!  Mitsubishi has a non bladder tank that , at least in my experience, is prone to pin hole leaks at welded joints after time.  Ants are a problem no matter what brand.

[bankruatsteve]

If you like to have the "best" and can afford it, then go for Grundfos.  I assure you that you really don't need it though.  A 250 W Hitachi/Mitsubishi will adequately handle what you have described.  BTW: the noise from the H/M is not that much more than Grundfos so not really an issue.

[lopburi3]

1 hour ago, bankruatsteve said:

If you like to have the "best" and can afford it, then go for Grundfos.  I assure you that you really don't need it though.  A 250 W Hitachi/Mitsubishi will adequately handle what you have described.  BTW: the noise from the H/M is not that much more than Grundfos so not really an issue.

Do not agree at all.    

 

The Grundfos is much more quiet than others (and in city (Bangkok) that can become an issue with neighbors) and will provide a normal water pressure rather than the well pump pressures of Mitsubishi.  As OP is talking a rain shower with unknown requirements for water volume/pressure in a large 2 story home believe he well advised to pay the extra for a pump that can deliver.  And I had experience with Mitsubishi over 400 watt units and they were totally negative in comparison with Grundfos.  But I will agree the smaller pumps will often provide good service if you are willing to accept moderate shower water flow - but remember most things will take longer with less water flow. 

[Langsuan Man]

12 hours ago, lopburi3 said:

The Grundfos is much more quiet than others

Having had both a Grundfos and a Hitachi in the same location I can attest to the quiteness of the Grundfos

 

Everytime I flush the toilet I can hear the Hatachi turn on but when I had the Grundfos it was virtually silent 

 

Only replaced the Grundfos because of an inept service person from Fagor, who claimed the Grundfos was the cause of my "fluctuating" hot water pressure.  Same problem with the Hitachi which was eventually traced to a defective shower and sink valve

 

 The TG is enjoying the quiet Grundos in her Korat house,  much to my dismay 

[bankruatsteve]

No disagreement that Grundfos is quiet.  I have Hitachi GW series which I can faintly hear from inside the house when it comes on.  It is certainly not annoying even standing next to it.  Actually, it's an alert of sorts to water usage and when it stays on, I know a tap didn't get fully turned off or a toilet needs a joggle.  The point was, that a 250 W pump can adequately service a two floor home to the satisfaction of most folks.

[Crossy]

We got MiL one of these https://www.directtoshop.com/product/277586 to run the toilet block (bog, showers, washer), very good for the money and is self priming so can draw from a shallow well or bore.

 

But, it's a peripheral (rather than centrifugal) pump and it really screams when under load (like one shower), I'll swear you can hear it in the next village over Puyai Baan on the speakers.