I'm thinking of getting some under sink water heaters at work, I was
going to fit a boiler but thinking that as we use hot water merely for
hand washing, rinsing cups etc these could be more cost effective than
having the boiler running while the hot water eventually materialises.
(Opinions on that would be appreciated though, given the cost difference
between gas/electric)

Then if going for the under sink units, would gut instinct lead one to
get ones with or without a tank (thinking 10/15l)?

Cheers.

On Monday, 24 September 2018 12:51:32 UTC+1, R D S wrote:
Then if going for the under sink units, would gut instinct lead one to
get ones with or without a tank (thinking 10/15l)?

You will need a tank.

Instantaneous ones are okay for handwashing in toilets but for anything more than a lukewarm dribble you will either need 7kW+ and dedicated wiring, or a tank.

Being unvented they need a pressure relief valve and discharge pipe, and in most cases a pressure vessel too. The over-sink vented ones are easier to install, but because the outlet tap is vented they drip.

Owain


Owain

On 24/09/2018 12:51, R D S wrote:
I'm thinking of getting some under sink water heaters at work, I was
going to fit a boiler but thinking that as we use hot water merely for
hand washing, rinsing cups etc these could be more cost effective than
having the boiler running while the hot water eventually materialises.
(Opinions on that would be appreciated though, given the cost difference
between gas/electric)

Then if going for the under sink units, would gut instinct lead one to
get ones with or without a tank (thinking 10/15l)?

Cheers.

If you want a sinkfull of water at a time, get one with a tank as long
as there is space. If you really only need a dribble for hands or cups
one at a time, an instantaneous should be fine. There are also over sink
heaters of both types, they take up some space but are easier to fit.

On 24/09/2018 13:55, wrote:
On Monday, 24 September 2018 12:51:32 UTC+1, R D S wrote:
Then if going for the under sink units, would gut instinct lead one to
get ones with or without a tank (thinking 10/15l)?

You will need a tank.

Instantaneous ones are okay for handwashing in toilets but for anything more than a lukewarm dribble you will either need 7kW+ and dedicated wiring, or a tank.

Being unvented they need a pressure relief valve and discharge pipe, and in most cases a pressure vessel too. The over-sink vented ones are easier to install, but because the outlet tap is vented they drip.

They used to be called Sadia Heaters. Mostly over sink, with a long
spout you swung across the sink, which, as you indicated, dripped as it
was heating up.

I was in a place which had an under sink heater which worked the same
way: the hot water tap looked like a conventional tap but the knob
worked a long rod that controlled the inlet to the heater in the same
way as the over sink kind.

--
Max Demian

In article , Max Demian
wrote:
On 24/09/2018 13:55, wrote:
On Monday, 24 September 2018 12:51:32 UTC+1, R D S wrote:
Then if going for the under sink units, would gut instinct lead one to
get ones with or without a tank (thinking 10/15l)?

You will need a tank.

Instantaneous ones are okay for handwashing in toilets but for anything
more than a lukewarm dribble you will either need 7kW+ and dedicated
wiring, or a tank.

Being unvented they need a pressure relief valve and discharge pipe,
and in most cases a pressure vessel too. The over-sink vented ones are
easier to install, but because the outlet tap is vented they drip.

They used to be called Sadia Heaters.

Sadia was simply one make.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 24/09/2018 12:51, R D S wrote:
I'm thinking of getting some under sink water heaters at work, I was
going to fit a boiler but thinking that as we use hot water merely for
hand washing, rinsing cups etc these could be more cost effective than
having the boiler running while the hot water eventually materialises.
(Opinions on that would be appreciated though, given the cost difference
between gas/electric)

Then if going for the under sink units, would gut instinct lead one to
get ones with or without a tank (thinking 10/15l)?

I would probably go for undersink unvented. The smaller ones have less
difficult control requirements than the full size ones.


--
Cheers,

John.

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On 24/09/2018 12:51, R D S wrote:
I'm thinking of getting some under sink water heaters at work, I was
going to fit a boiler but thinking that as we use hot water merely for
hand washing, rinsing cups etc these could be more cost effective than
having the boiler running while the hot water eventually materialises.
(Opinions on that would be appreciated though, given the cost difference
between gas/electric)

Then if going for the under sink units, would gut instinct lead one to
get ones with or without a tank (thinking 10/15l)?

Cheers.

How much do you want to spend? We've got a Quooker under-sink boiling
water heater in our kitchen, which is very good - but expensive.

This holds 7 litres of boiling water in an insulated container. It has a
boiling water tap - which can be used for making tea or coffee without
needing a kettle. It also has a mixing valve to feed mixed boiling/cold
water (in other words *hot* water) to the sink's hot water tap for hand
washing and washing up.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On 24/09/2018 12:51, R D S wrote:
I'm thinking of getting some under sink water heaters at work, I was
going to fit a boiler but thinking that as we use hot water merely for
hand washing, rinsing cups etc these could be more cost effective than
having the boiler running while the hot water eventually materialises.
(Opinions on that would be appreciated though, given the cost difference
between gas/electric)

Then if going for the under sink units, would gut instinct lead one to
get ones with or without a tank (thinking 10/15l)?

Provided that you can educate people not to turn the tap on and walk
away until it runs hot then the 10/15L under counter hot water heater
will be fine. You have to provide an escape for over pressure and meet
certain mains water pressure requirements which may require an expansion
chamber and pipework to an external overflow/steam vent.

We have them in our village hall. They are fine in toilets but less good
in a position where a lot of washing up might be done in a short space
of time. I regret not having a 7kW flash boiler type fitted on their
downstairs kitchen sink (it is about 3m from the main fusebox).

Worth putting them on timeswitches - as they do consume a bit too much
power for my liking on standby full of ready to use hot water.

--
Regards,
Martin Brown

On Monday, September 24, 2018 at 12:51:32 PM UTC+1, R D S wrote:
I'm thinking of getting some under sink water heaters at work, I was
going to fit a boiler but thinking that as we use hot water merely for
hand washing, rinsing cups etc these could be more cost effective than
having the boiler running while the hot water eventually materialises.
(Opinions on that would be appreciated though, given the cost difference
between gas/electric)

Then if going for the under sink units, would gut instinct lead one to
get ones with or without a tank (thinking 10/15l)?

Cheers.

The heaters with tanks are very expensive and store hot water which is a waste if you don't need it all the time. I have an instant under counter water boiler running off cold mains water so the water is very hot in summer and warm in winter which is no hardship. You can get them on ebay made in Eastern Europe for about £55 and work on a ring main so no special wiring (ie cooker /shower cable) up to 5.5 kw but do check with an electrician. You will need a vented tap though.
https://www.ebay.co.uk/itm/5-5KW-DAF...gAAOSwKsZben2B

My advice is go for the over counter dripping variety.

On Tuesday, 25 September 2018 12:13:21 UTC+1, alanjones wrote:
...work on a ring main so no special wiring (ie cooker /shower cable)
up to 5.5 kw

Anything above 3kW MUST go on a suitable radial circuit

Some would say 2kW.

Owain

In article ,
Max Demian wrote:
I was in a place which had an under sink heater which worked the same
way: the hot water tap looked like a conventional tap but the knob
worked a long rod that controlled the inlet to the heater in the same
way as the over sink kind.

There's also a version that uses a mixer tap with three ports: cold
water in, cold water out to the heater, and hot water back from the
heater.

Example: https://www.tlc-direct.co.uk/Products/HHHF05MVC.html

Advantages: very simple installation, not too pricey

Disadvantages: single tap only, dribble from the tap as the water
heats up

Steve
--

On 25/09/2018 12:13, alanjones wrote:
On Monday, September 24, 2018 at 12:51:32 PM UTC+1, R D S wrote:
I'm thinking of getting some under sink water heaters at work, I
was going to fit a boiler but thinking that as we use hot water
merely for hand washing, rinsing cups etc these could be more cost
effective than having the boiler running while the hot water
eventually materialises. (Opinions on that would be appreciated
though, given the cost difference between gas/electric)

Then if going for the under sink units, would gut instinct lead one
to get ones with or without a tank (thinking 10/15l)?

Cheers.

The heaters with tanks are very expensive

They start at around £80

and store hot water which
is a waste if you don't need it all the time.

If they are well insulated, that should be less of a worry. However it
will depend a bit on how often the hot water is required.

I have an instant under
counter water boiler running off cold mains water so the water is
very hot in summer and warm in winter which is no hardship. You can
get them on ebay made in Eastern Europe for about £55 and work on a
ring main so no special wiring (ie cooker /shower cable) up to 5.5 kw
but do check with an electrician.

A 5.5kW load is *not* suitable for connecting to a general purpose
socket circuit.

It needs a dedicated circuit. That *could* be a ring if you wanted, but
there would be no advantage in it being so.



--
Cheers,

John.

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| Internode Ltd - http://www.internode.co.uk |
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