Plumber question - Gravity fed system....

boarduser01

I have a question - my plumber is proposing putting in two tanks, one out in the garage and one smaller one in the loft to feed into via a pump.

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does this mean that each time we turn on a tap in the house the pump will operate? So each time we use water we use electricity, have I got this right?

What is wrong with the old traditional gravity feed system? Why would it be necessary to use electricity to operate supply of water to the taps????

How high above a shower would a gravity fed tank have to be to enable it to work ok?

Would it be possible to have most taps fed by gravity and then just the showers fed by a pump system if necessary???

Please reply soon as I don't want to go down the pump using route if possible.

muffler

You will probably get more replies in DIY

Moved

10-10-20

Your setup is somewhat unclear, but he may simply be proposing that the pump be on the shower piping instead of between the main and secondary tank.
Personally, I wouldn't like a pump-fed secondary tank as the chances of the switching device failing and overfilling the tank are great.

Maybe clarify exactly where he wants the pump?

silverharp

We have Euopean type bathware so our plumber put a pump in that powers everything except the tap in the kitchen sink. But we still only have the one tank in the attic.

galwaytt

boarduser01 wrote:

I have a question - my plumber is proposing putting in two tanks, one out in the garage and one smaller one in the loft to feed into via a pump.

---

does this mean that each time we turn on a tap in the house the pump will operate? So each time we use water we use electricity, have I got this right?

not necessarily, you only use electricity when the pressure in the system drops below a certain level, and the pump tops up the attic tank - what you're describing is still a gravity system, but with the tank that supplies the gravity system need to be pumped.........maybe there's poor mains pressure where you are, and the plumber is addressing foreseeable issues...........

What is wrong with the old traditional gravity feed system? Why would it be necessary to use electricity to operate supply of water to the taps????

poor quality of water supply, poor pressure, may not meet the needs of modern appliances (e.g. power and/or electric showers), to long to empty 'dead legs' etc etc, the list goes on........the amount of power used is small.

Would it be possible to have most taps fed by gravity and then just the showers fed by a pump system if necessary???

yes, but you're re-introducing the scald feature........you know, the one where someone uses the cold, and you get scalded in the shower at the time..........proper presssure systems mitigate that possibility...../QUOTE]

311

Theres nothing wrong with using a pump for domestic hot and cold water supplies.
In germany they don't use tanks.

Alun

_Brian_ wrote:

There's nothing wrong with using a pump for domestic hot and cold water supplies. In Germany they don't use tanks.

They don't use them in lots of (most?) places on the continent, but that's because the mains pressure is consistent and guaranteed, not (I assume) because they use pumps in domestic installations. At least when I lived in Germany and Holland they didn't.

311

Your more than likely spot on alun ,I'm just going by what I've been told.

I know in spain that they have a communal water supply ,that feeds high powered showers. But your into privitisation and water districts then and that means jobs ,etc etc.

I personally like the way it is ,it's very transparent at the moment (thats not meant to be funny).

Privatisation of water ,would mean the euro coming along all over again.:mad:

DublinWriter

In my own case, the original plumber fitted 1/4 inch pipes from the feed tank in the attic to the gas boiler in the utility room.

These weren't sufficient and led to the boiler not firing because there wasn't sufficent pressure.

A plumber suggested either replumbing the house (expensive as ceilings would also have to come out and be re-plastered) or would fit a pump in the attic.

I wasn't initially thrilled with the idea of a pump as it's something new that can go wrong eventually.

The workaround we came up with was to feed the boiler from the mains supply at ground level.

This fixed the problem.

galwaytt

DublinWriter wrote:

The workaround we came up with was to feed the boiler from the mains supply at ground level.

This fixed the problem.

I hope that connection was temporary, and is not left connected.........you are not allowed to have heating systems connected to potable water.

There is the possibility that stale, contaminated water, and other nasties, could cross into the mains feed, so polluting your drinking water. DHW and drinking water systems cannot be left connected to one another..........

boarduser01

Thank you for all the replys,

10-10-20 wrote:

Your setup is somewhat unclear, but he may simply be proposing that the pump be on the shower piping instead of between the main and secondary tank.
Personally, I wouldn't like a pump-fed secondary tank as the chances of the switching device failing and overfilling the tank are great.

Maybe clarify exactly where he wants the pump?

10-10-20 - the plumber is indeed suggesting putting the main large tank in the garage, and then using the pump to move the water into the secondary smaller tank in the roof of the house. You have confirmed my fears that the pump could malfunction and cause us problems....

Galwaytt - I thought that the secondary tank would need to be re-filled up to the correct level each time water is used, so would that not mean that each time a tap is turned on the pump from the main tank would come on to refill the secondary tank??? or am I not understanding how it works?

Thanks again for any help you can offer.

10-10-20

boarduser01 wrote:

10-10-20 - the plumber is indeed suggesting putting the main large tank in the garage, and then using the pump to move the water into the secondary smaller tank in the roof of the house. You have confirmed my fears that the pump could malfunction and cause us problems....

Don't take it clean-cut from me - best talk to your plumber about your concerns, he has installed these before I'm sure!
I would be looking for a backup solution to prevent flooding should a switch fail, a normal 1/4 in overflow pipe from the smaller tank may not take the flow that the pump is producing from the larger tank, so find other solutions to the problem!

galwaytt

boarduser01 wrote:

Galwaytt - I thought that the secondary tank would need to be re-filled up to the correct level each time water is used, so would that not mean that each time a tap is turned on the pump from the main tank would come on to refill the secondary tank??? or am I not understanding how it works?

Thanks again for any help you can offer.

I think there's confusion here on which tank does what. I took it to mean that Dublinwriter's plumber connected the actual mains to the CH system. If he did, that's a no-no and should be undone asap.

In a normal gravity situation, the cold water to your sink comes from mains directly, not from any tank. This way you are not drinking stagnating water. The main cold water tank in that attic feeds the toilets, appliances etc etc. The other, secondary tank in most people's attics feeds the heating system, and has it's own connection via a ballcock. If the CH system level goes down, it tops itself up, with no interference with the domestic system, and so no cross over of contamination issues.........

However, I think you are describing the main tank in your attic as the secondary (in your pumped scenario). Again, the issue of drinking stagnating water comes in to play. It is worth thinking about this, and maybe connecting your kitchen tap to your new bulk tank with pump in such a way that your kitchen gets effective fresh water on demand, but without taking it out of a tank which gets it out of another tank...........if you get my drift. For all other purposes, a bulk tank feeding one in your attic is fine.)

There is no reason not to use a pumped solution - current draw is very small, and sporadic. Overflow can occur in any plumb type, and you should always have an overflow.......so don't let that put you off.