Loft Conversion - Removing Water Tank

[NHW]

I am considering having a loft conversion in my property, i know that there are 2 water tanks in the loft (large one for the bath, small one for the central heating) but i would rather do without these in the loft because i am after as much space as possible in the loft and having to build around two tanks would obviously take up a needless amount of space.

I'm not a plumbing expert but i think my system is a conventional one at the moment (boiler in kitchen, cylinder in airing cupboard, water tank in loft).

Also Since we have moved into the property the water pressure in the shower has been quite non-existent, it basically just feels like its dripping out of the shower head instead of actually pressuring out, so this was something already on our 'to-do' list.

So for the purpose of:

1. Getting rid of the need of water tanks in the loft
2. getting more pressure from the water

Would i need a specific type of boiler to meet the requirements above?

I will list the amount of rooms that have water outlets just incase this is needed:

Downstairs toilet - taps & toilet
Kitchen - taps
Bathroom - toilet, bath, taps
upstairs en suite - toilet, shower, taps

 

[D_Hailsham]

Depending on how many live in the house, you may get away with a combi boiler. But a safer option is a System boiler and an unvented HW cylinder.

In either case you need a good incoming cold water flow rate and pressure.

If you have a garden tap, measure the flow rate when it is fully open (litre marked bucket and watch). Then repeat with the kitchen cold tap on at the same time. You need at least 20 litres/min for test 1 and 10 lpm for test 2.

If less than that, you may have to upgrade the incoming cold water main.

 

[ALCPlumbing]

Depending on how many live in the house, you may get away with a combi boiler. But a safer option is a System boiler and an unvented HW cylinder.

In either case you need a good incoming cold water flow rate and pressure.

If you have a garden tap, measure the flow rate when it is fully open (litre marked bucket and watch). Then repeat with the kitchen cold tap on at the same time. You need at least 20 litres/min for test 1 and 10 lpm for test 2.

If less than that, you may have to upgrade the incoming cold water main.

+1

To do away with the smaller tank which is your header tank for your heating system you will need to either convert your current system to a sealed system. You don't necessarily need to replace the boiler to do this.

The larger tank is your cold water storage tank which feeds your hot water cylinder and the cold water supplies to your bathroom. To remove this you will need to convert both the hot and cold water supplies to be run directly from the mains. This can be achieved by replacing boiler with a combi boiler. Most combi boilers require a sealed heating system so would need both tanks removed anyway but they don't have the best flow rate for hot water production. If you will have more than one bathroom it will not cope with the demand for hot water. This means you would probably be better off having an unvented hot water cylinder installed. This woldnt require replacing the boiler but as previously mentioned will most probably require the upgrade of your incoming water main.

 

[rjm2k]

If they are in the middle of the loft space, it may be possible to move them to one end and keep them without losing too much space.

 

[D_Hailsham]

If they are in the middle of the loft space, it may be possible to move them to one end and keep them without losing too much space.

But that won't solve the OP's pressure problem.

 

[Plumber90]

I have sent you a private message NHW

 

[NHW]

Hi guys sorry for the late reply. Have just had a bit of free time to carry out the test. i didnt have a 20L container but had one that was 5L so i just multiplied by 4.

To get 5L from the garden tap it took 20 secs, so to get 20L i am assuming it would take about 1min 20 secs which i already assume is already too low?

If the case if that it would cost too much in order to remove the tanks then i might just try keep them and build around them.

But should i be worried that i don't actually have much pressure in my system already?

1. the water pressure form the ensuite is non-existent
2. Whenever we fill a bath both the hot and cold water always run out when the bath is about 2/3 full, and this when no hot water has been used throughout the day.

 

[ALCPlumbing]

As your system is tank fed you won't have any pressure. That is normal. However, your cws tank running dry is a problem as it is clearly undersized or is not filling properly. There may be a problem with the ball valve.