Electric water heater to top up communal heating

[Chillireg]

Can I boost my communal hot water supply at or close to the bath tap?Instant hot water heater?

I live in a flat with a communal water system. The hot water for the bath goes lukewarm when the heating is on. There is no option to change this. I want to install something in line that will boost the hot water temperature either automatically or manually . I would only need to add extra hot water to boost the water temp not heat from scratch. I envisage either 1) I run the bath with luke warm and then switch the magic heater on which delivers some extra hot water or 2) I run the bath - the magic heater senses that the temp is low and boosts - if I think this is taking forever and I probably have enough superhot water I can easily reach into the cupboard and drop the temp so that the rest of the bath fills up easily. I don't have unlimited space for this - but I do have a height of possibly 250 mm.

[mikebradford]

Lots of electric heaters have a form of storage incorporated within differing sized vessels.
We have one in our office toilet.
Sits under the sink and delivers very hot water.
That's topped up by a cold supply.
So if topped up by a hot supply I assume it would be quicker to supply hot water if run down.

Would need to be sized for your use.

https://www.screwfix.ie/p/ariston-andris-lux-under...

[OutInTheShed]

Add a kettle or two of boiling water?

[Chillireg]

True True but l think it’s more like 5 or 6

[Rough101]

The communal system should really be hitting your taps or mixer inlet at 50 degrees or it’s a legionella risk.

Unless what you have is a heat interface unit and the water is just heated locally within your flat via that?

[Chillireg]

Understood but the communal hot water does get that high except when the heating is on

[Sheepshanks]

Chillireg said:

Understood but the communal hot water does get that high except when the heating is on

Your heating, or everyone's heating?

[Chillireg]

Don’t know but indications are that the hot water goes into heating - it gets worse if there’s a lot of hot water demand- this suggests system constraints coupled with tank size - there is no point pursuing options to change the communal hot water - l need a small solution l control - all the rest is theory and beyond my control I‘m afraid

[Sheepshanks]

I wonder if a Willis heater would do the job? Might be too small capacity to be useful - I don't know if they work to any extent continuously.

[GasEngineer]

Chillireg said:

there is no point pursuing options to change the communal hot water..

If the system is not working properly then why can't whoever is responsible for it get it sorted?

I don't think there is anything small enough for the space you have, Something like a Stiebel Eltron MegaBoost Tank would do the job if you have the space,

https://www.stiebel-eltron.com/static/ste/docporta...

[Chillireg]

Thanks- I‘ve been looking at a similar one made by Zip - just unfortunately will have to get a separate RCD for it - it won’t just plug in

[TVR Sagaris]

What sort of communal heating system do you have? As others have said I can't see that it's working properly if you lose temperature in the way you describe.

Is there a big gas boiler somewhere? Do you have a hot water tank in your house?

[Chillireg]

Possibly not but there is nowt to be done for various reasons hence me getting my own solution

[Sheepshanks]

Chillireg said:

Thanks- I ve been looking at a similar one made by Zip - just unfortunately will have to get a separate RCD for it - it won t just plug in

Something you can plug in would be hopeless - you might as well boil kettles. Imagine if you filled a kettle with your "hot" water and boiled it over and over again - that's what a plug-in heater would be doing.

Do you know the temperature of your hot water? I think it would need every bit of a 7-8kW heater (so a 40A supply) to make a worthwhile difference in terms of temperature rise at a reasonable flow rate.

[Chillireg]

yeah I've accepted I'll need 8kw -I'll just have to bite the bullet

[GasEngineer]

Chillireg said:

yeah I've accepted I'll need 8kw -I'll just have to bite the bullet

Still don't get why those responsible for the system won't remedy the fault.

If you could give more detail about the existing system we may be able to advise. It may be fairly straightforward.

[Chillireg]

thanks but these are 10 year old wood pellet boilers - the situation is delicate and I agree they should but it would appear they can't or won't and I have decided a little independence here is no bad thing

[Chillireg]

thanks but these are 10 year old wood pellet boilers - the situation is delicate and I agree they should but it would appear they can't or won't and I have decided a little independence here is no bad thing

[Chillireg]

Sheepshanks said:

I wonder if a Willis heater would do the job? Might be too small capacity to be useful - I don't know if they work to any extent continuously.

Just looked at this - maybe this IS an option - do you have any experience of them?

[Snow and Rocks]

Far from ideal but an electric shower is probably about as good as you're going to get for a sensible price that will fit in that space.

It will still need an electrician to run power but it will instantaneously heat water indefinitely and is about as powerful as can be sensibly run from the mains.

Flow rate will be crap with cold water fed in but might be approaching reasonable if you feed it with warm water.