Need more hot water

Naf

So my idea for getting an electric shower fitted is out; but we're still really short on hot water. The hot water is totally gone (especially in this weather) within a half hour of the shower running. With two adults & three kids it just doesn't work. The boost function is all well & good; but takes time to reheat, and doesn't heat all that much.
Unfortunately the 'cupboard' where the current tank is situated can't handle anything bigger (the larger tanks are wider too, and that just won't fit), so I have the idea of getting an additional tank fitted in the attic? Is this a possible/realistic idea?

smudger1964

combi boiler? unlimited hot water

HappyMJ

Naf wrote: »

So my idea for getting an electric shower fitted is out; but we're still really short on hot water. The hot water is totally gone (especially in this weather) within a half hour of the shower running. With two adults & three kids it just doesn't work. The boost function is all well & good; but takes time to reheat, and doesn't heat all that much.
Unfortunately the 'cupboard' where the current tank is situated can't handle anything bigger (the larger tanks are wider too, and that just won't fit), so I have the idea of getting an additional tank fitted in the attic? Is this a possible/realistic idea?

I would leave the hot water on all the time.

To save money with an electric immersion you can take the top off and turn the thermostat down to...let's say 50 degrees...so that only the bottom immersion heater is mostly used to reheat the water to 70 degrees (turning it up higher will give you more hot water) at night and the top immersion would only kick in once the water has cooled quite a lot.

Gas heated water doesn't really matter. The thermostat has a 5 minute hysteresis so when the water does go below the set temperature the boiler will come on for at least 5 minutes reheating the water and won't come on again for many hours. Mine only comes on by itself twice a day if no hot water is used.

Naf

smudger1964 wrote: »

combi boiler? unlimited hot water

Economy 7; storage heaters & no gas to the property. Sorry; I should have been clearer.

I'm not even certain we have a proper E7 cylinder; there only seems to be one immersion heater - certainly only one wire going to the cylinder.

Canucklehead

Might be worth posting a photo.

Or two.

Or three.

Naf

Canucklehead wrote: »

Might be worth posting a photo.

Or two.

Or three.

What of? Unfortunately the current setup is a little difficult to get at right now.

There is (or I should say there must be - its virtually inaccessible) a header tank in the loft space - we're getting a proper ladder fitted to this very shortly and will be putting down flooring panels for storage.
The tank (which I did my best to measure) seems to be a 450mm diameter 900mm tall version, so 120L. It definitely has only one wire going to it, and only seems to have one immersion heater insterted. I re-lagged it myself, and there's no controls/wires or anything to indicate anything more.
The control box I could post a photo to, but it's pretty typical for E7 as I've gathered. No option for always on; a switch for 'off/timed' operation; a clock dial with sliders to set 'on/off' times overnight; and a 1hr dial for the boost function (which I assume must just power the same immersion heater as overnight).

HappyMJ

Naf wrote: »

What of? Unfortunately the current setup is a little difficult to get at right now.

There is (or I should say there must be - its virtually inaccessible) a header tank in the loft space - we're getting a proper ladder fitted to this very shortly and will be putting down flooring panels for storage.
The tank (which I did my best to measure) seems to be a 450mm diameter 900mm tall version, so 120L. It definitely has only one wire going to it, and only seems to have one immersion heater insterted. I re-lagged it myself, and there's no controls/wires or anything to indicate anything more.
The control box I could post a photo to, but it's pretty typical for E7 as I've gathered. No option for always on; a switch for 'off/timed' operation; a clock dial with sliders to set 'on/off' times overnight; and a 1hr dial for the boost function (which I assume must just power the same immersion heater as overnight).

Where in the cylinder is the immersion? The top...or the bottom. You will get more heat from an immersion at the bottom. The immersion element at the top will not heat the whole cylinder it will only heat a third so you have enough for washing hands and dishes. Heat rises.... Is there a space for an element at the bottom? Any other holes on the cylinder where pipes could be fitted? 120L is too small for your usage (5 persons) so I'd consider replacing with a larger cylinder possibly 240L. A 120L cylinder would be fine if you had gas to heat it as it will reheat by the time the next person uses it. Normal hot water usage is around 50 litres per person per day but will be much less if the washing machine heats it's own water and the dishwasher heats it's own water and if you had an electric shower. You might get away with 180L.

Naf

HappyMJ wrote: »

Where in the cylinder is the immersion? The top...or the bottom. You will get more heat from an immersion at the bottom. The immersion element at the top will not heat the whole cylinder it will only heat a third so you have enough for washing hands and dishes. Heat rises.... Is there a space for an element at the bottom? Any other holes on the cylinder where pipes could be fitted? 120L is too small for your usage (5 persons) so I'd consider replacing with a larger cylinder possibly 240L. A 120L cylinder would be fine if you had gas to heat it as it will reheat by the time the next person uses it. Normal hot water usage is around 50 litres per person per day but will be much less if the washing machine heats it's own water and the dishwasher heats it's own water and if you had an electric shower. You might get away with 180L.

The element is seated in the curved dome; but I've always assumed it drops a reasonable length down inside and doesn't just sit right at the top. We do seem too get a full tank as the bottom of the cylinder was always warm when I checked (back before the baby's cot blocked the cupboard).
I never noticed any other ports to fit another heater near the bottom.
I originally wanted to look at a larger cylinder, but this one only just fits in the cupboard (the lagging is very flattened at the back, and pressed tightly against the door when closed). When I look up sizes, anything bigger is at least 5cm wider so simply won't fit.
I agree that a properly fitted 180l might just cover us now; but once the kids are a bit bigger I suspect we'll need more again. Luckily we have a dishwasher and laundry machine that heat their own.

Mr_Ted

smudger1964 wrote: »

combi boiler? unlimited hot water

:rotfl:Wouldnt be so !!!! sure about that comment :rotfl:

Mr_Ted

Sounds like a pretty old cylinder, so it might be scaled or even the immersion or immersion stat knacked, this needs checking, but sounds like a refit is the option i'm afraid!

Naf

Mr_Ted wrote: »

Sounds like a pretty old cylinder, so it might be scaled or even the immersion or immersion stat knacked, this needs checking, but sounds like a refit is the option i'm afraid!

The existing cylinder seems to heat the water just fine - just the amount of water it holds isn't enough.
After considering a new cylinder, and realising that nothing larger would fit; my question is still would it be possible/reasonable to fit an additional cylinder into the loft which heats overnight as an additional source.
So essentially the water would flow from the header tank, into the additional loft tank, then down to the existing tank before heading to the taps. As I understand the physics of it, so long as the ultimate exit is lower than the starting point, and the system is sealed full of water, this shouldn't cause any issues with flow.