Large loft tank

[dunny]

I have posted before about issues we have at this house with low water pressure. Cut a long story short rather than using a break tank (which I was considering) we will be connecting to a supply 450m away but its going to be some time before this can happen.

In the meantime if I put a large tank in the loft and increase the size of the hot water cylinder am I likely to see a noticeable difference in pressure? In particular I would like to improve the pathetic shower - would the plan above work?

I appreciate the tank will take longer to fill and it may result in constant(ish) refilling of the tank but it would be better than what we have now (assuming the plan would work).

Any advice on sizes to support a family of four?

Space in the loft isn't an issue.

Thanks

D

 

[JohnD]

the height of the cold water tank affects the pressure.

Size doesn't

If you can do rough carpentry to can make a strong platform to raise the tank by a metre or so. You still need to be able to get into the top to replace the ballcock.

BTW take great care not to drop an inspection lamp or other mains powered item into the tank.

 

[45yearsagasman]

Size isn't everything, it's how far up you can get it....................

 

[dunny]

the height of the cold water tank affects the pressure.

Size doesn't

If you can do rough carpentry to can make a strong platform to raise the tank by a metre or so. You still need to be able to get into the top to replace the ballcock.

BTW take great care not to drop an inspection lamp or other mains powered item into the tank.

I assume a greater water volume and lifting the height of the tank would make a difference? I think I could probably get the tank up by 2m if I used a coffin style tank.

Could I pump off this tank to improve the shower?

Could I replace the hot water tank with the same type (i.e. normal immersion heater) with a larger capacity one?

Thanks

D

 

[JohnD]

you can pump to the showers if you want to. Not to anything else, though, as the noise will be irritating.

You can get a bigger hot water cylinder if you like. The modern ones are well insulated. If you are going to use an immersion heater, have a cylinder that takes one near the bottom (to heat the whole contents) and one near the top, to heat a small amount of water more quickly. An immersion heater can heat roughly one litre per minute to tap temperature (a bit slower in winter as it starts colder). A bath takes about 100 litres. If you are going to upgrade the supply pipe for improved flow, consider an unvented cylinder which will still be useful afterwards.

Electricity is a very expensive source of energy.

 

[Madrab]

From the cold water cistern outlet, for every meter above the level of a given outlet e.g. shower head, you gain .1bar head of pressure.
Get it as high as possible and increase the feed to and the outlet from the hot water cylinder to 28mm, that will increase the flow, not the pressure, and then increase the capacity of the cylinder. Use outlets/showers that are low pressure compatible.

Alternatively it can easily be pumped.

 

[Steelmasons]

From the cold water cistern outlet.

At least someone knows the difference between a cistern and tank..

 

[dunny]

From the cold water cistern outlet, for every meter above the level of a given outlet e.g. shower head, you gain .1bar head of pressure.
Get it as high as possible and increase the feed to and the outlet from the hot water cylinder to 28mm, that will increase the flow, not the pressure, and then increase the capacity of the cylinder. Use outlets/showers that are low pressure compatible.

Alternatively it can easily be pumped.

Rob, if I raise the tank as high as I can and as you say increase the into and out of a larger cylinder would a pump then help me to increase the pressure? Would I pump from the hot side or the cold side?

Would this sort of thing do:-

http://www.ebay.co.uk/itm/ALBION-20...229289?hash=item1c7643a669:g:DPYAAOSw44BYJFCa

Or this:-

http://www.ebay.co.uk/itm/300-litre...490242?hash=item1ebcea4b82:g:UNwAAOSwiDFYPY9C
Thanks

D

 

[Madrab]

The HW cylinders you linked to run from the mains, they're un-vented cylinders. You need a vented cylinder that is fed from a gravity system like the one you will be installing. You add the pump in downstream of the hot and cold supplies in the supply pipe to the designated outlets.

 

[JohnD]

Is there an undesirable effect from using an unvented cylinder with a tank?

For a person who wants to buy a larger cylinder prior to upgrading the supply pipe?

 

[Madrab]

Yep, in simple terms, gravity cold water can't deliver the constant pressure needed to allow an un-vented to work properly and safely. I wouldn't recommend pumping a gravity cold water cistern supply into a un-vented cylinder, if I am reading between the lines correctly. Un-vented is usually a mains fed HW solution.

 

[dunny]

Yep, in simple terms, gravity cold water can't deliver the constant pressure needed to allow an un-vented to work properly and safely. I wouldn't recommend pumping a gravity cold water cistern supply into a un-vented cylinder, if I am reading between the lines correctly. Un-vented is usually a mains fed HW solution.

So I need a vented immersion heater cylinder, similar to what I have now but bigger.

As an example:-

http://www.ebay.co.uk/itm/HOT-WATER...738166?hash=item41b73770f6:g:5ZQAAOSwARZXmeqA

D

 

[Steelmasons]

Commercial use break break cisterns coupled with booster pump sets in order to supply unvented calorifiers.
A domestic stuart and turner won't cut it in this case..

 

[Madrab]

@Steelmasons ....

yes @dunny , a vented cylinder will do the job. I'd avoid second hand though, never know where its been or what it's been through.

 

[dunny]

Sorry....one more question.

The cylinder I have in is both an immersion heater and an indirect cylinder linked to the CH (I think). Could I leave this in, disconnect the immersion side and stick a separate cylinder in as well? If so could these then be connected to a single outlet supply and then pumped?