I'd like a inline mains pressure electric water heater for my kitchen.
However, I want to run it off the hot supply. The line to the heat bank in
the loft is around 20m, much of it in 22mm, so it takes an age for hot water
to come through. I'd just like to electrically heat until the hot water
comes through. I don't want to run a pumped return line for energy
When the hot comes through, I want a thermostat in the heater to cut the
power. Is there such a device available cheaply?
3kW should be enough (less if storage). I only want to wash my hands or
rinse something. If I'm filling the sink, I can wait for the proper heated
water to come through. I suppose it could be a storage unit or
instantaneous, provided it can feed a standard mixer tap at mains pressure.
On Wed, 7 Jan 2004 11:07:34 -0000, "Christian McArdle"
I have a feeling that to get reasonable flow of reasonably hot water,
you are going to need some level of storage. If you consider how poor
an electric shower is using 10kW, then 3kW is not going to be at all
good, although admittedly, since the water supply is going to be
inside the house, you would only be heating the water from, say, 20
degrees to perhaps 50 degrees rather than from 5 degrees.
This is probably going to imply a storage device of some sort.
Just as a thought on this, have you thought to consider the energy
required to maintain the water in a stored electric heater like this
at electricity unit prices, vs. running an insulated, pumped loop
heated by gas? I havne't done the sums, but there might not be
anything in it.
To email, substitute .nospam with .gl
I'm not so sure. I only want it for handwashing. There are many
instantaneous handwash units at the 3kW mark. If I want more than that, I
can just open up the tap and wait for proper hot water. I also want it as
cheap as chips. Perhaps I could modify a cheap bottom of the range shower
with an additional flow switch. Running a new cable to the consumer unit
would be simple. The problem is that I need something that doesn't restrict
flow too much, as I don't want to reduce the flow rate when it is running
off stored energy.
I don't imagine that a 7 litre hideaway unit will lose that much energy.
There is space for a lot of insulation. The pumped loop would be a nightmare
to install as well. It has to go up two floors and across the length of the
house. If I did it, I'd replace by 15mm rising main with 22mm and use the
15mm for the loop, but there is no opportunity to add insulation to the
existing pipework, which is buried in the wall, so it would be an energy
efficiency nightmare. It can't be surface mounted and boxed in, either, as
it runs up the centre of a wall.
If it is more than about 40w you will probably have other
worries, especially in summer. 20 quid a year running
costs make it hard to justify buying a fancy shower unit.
A 7 litre store with a tiny immersion heater?
On Wed, 7 Jan 2004 12:22:42 -0000, "Christian McArdle"
I see what you're saying. Might be a tall order.
The instant heaters all seem to be of the 7kW+ rating, storage ones at
3kW. Some have restrictions on the type of tap you can use - e.g. not
mixer taps or require vent taps. They warn about not having non return
valves on the feed side.
I looked at the installation instructions of a couple like the
Triton and they talk about flow restrictors. Perhaps those could be
left out. I couldn't see anything that said that you can't use a hot
supply as the fee, but nothing that said you could either.
Would it perhaps be more practical to take a cold feed and then run
the output to a separate small tap like the kind used for fitted water
filters. I've seen these used in the U.S. and in Germany quite
It's certainly the obvious solution. Unfortunately, I doubt it would go with
the general old oak and range cooker theme of the kitchen. The current taps
are burnished brass with "Chaud" and "Froid", and old style handwheels.
(Still ceramic cartridge, though, I hate compression valves!)
Besides, any guests would starting filling up their glasses from the
I'm inclined to agree. Unless I can find a simple bolt on inline 3kW heater
for around the 50 quid mark, I think I might not bother.
IIRC December's plumbing trade mag (voted saddo read of the year in a recent
uk.d-i-y poll ;-) had a couple of ads for pipe heating tapes for keeping
water hot at the taps between draw-offs. If I could find the mag in the
clutter here I'd give you some more details.
I read a book on improving your memory but I've forgotten what it was
Unfortunately, the pipe runs immediately into a channel in the wall under
the plaster. No chance of insulation. And I'm not replacing the run through
the loft space, even if it means the old run can be used for the condensate
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