2 - Water tanks, do they have to be the same size?

[Orangutan]

My plumber told me that the water tank that is going on the roof (4th floor), has to have a matching tank on the ground floor of the same size, so he can make sure that they are balanced/adjusted? The lower tank will be filled directly by the water provided by the MWA at the street, it will then be pumped up to the tank on the roof.

My original thought was to put a 1000 liter tank on the roof, and 400 liter tank on the ground floor. Since the ground floor tank will be inside my kitchen I was hoping for a smaller tank.

-O

[noikrit]

Simple answer NO .. Look at a resevoir on the land, then look at the size of the " Header" pressure tank on the hill to service the village by gravity ... Totally different... BUT ... make sure you are set up with a cut off valve when the "header " Tank is full or you'll have water everywhere ! CHOKDEE !

PS The beauty of having a large " header ' or gravity tank is the amount of reserve water you'll have when power/ village water is cut off

Edited November 9, 2013 by noikrit

[overherebc]

Simple answer NO .. Look at a resevoir on the land, then look at the size of the " Header" pressure tank on the hill to service the village by gravity ... Totally different... BUT ... make sure you are set up with a cut off valve when the "header " Tank is full or you'll have water everywhere ! CHOKDEE !

PS The beauty of having a large " header ' or gravity tank is the amount of reserve water you'll have when power/ village water is cut off

Will have water yes, but to operate a shower etc at 15 psi ( average ) you need it to be at 15 metres.

[lopburi3]

Not sure how he plans to control the pump but there should not be any such need. You should never have a dry tank on the roof so refill at 300 down should be fine and should not result in a dry lower tank. I would also want a pump on roof to provide more than gravity pressure to taps.

[Orangutan]

lopburi3, on 09 Nov 2013 - 08:52, said:

Not sure how he plans to control the pump but there should not be any such need. You should never have a dry tank on the roof so refill at 300 down should be fine and should not result in a dry lower tank. I would also want a pump on roof to provide more than gravity pressure to taps.

Thanks all .. I'd say that the roof is 50+ feet high. Yes a pump on the roof, and a Gundfos pump from the ground tank to the roof. I was told that I need a ball valve at the ground location, or an adjustable electrical float, to make sure the roof tank won't flood the ground tank.

Thanks - O

[IMHO]

The only purpose of the ground level tank is because it's generally not allowed to directly pump the mains (though many still do ). Maybe your installer fears that the ground pump will outperform the mains' ability to fill the ground tank? That could create a problem when commissioning the system.

The upper tank should fill from the top and have a mechanical float valve (i.e. standard setup) - which means there's no need for a one-way valve to stop water flowing back. No need for any fancy electronics

The ground level pump is the only challenge - you'll need to make sure the pump you get has enough head height to get the water up comfortably. Agree that a small pump on the roof is a good idea, if you want good water pressure above the ground floor.

Edited November 10, 2013 by IMHO