We're considering a small under-sink unvented water heater for our
kitchen as it's so far from the hot water tank it takes several
minutes (and lots of wasted water) for hot water to reach it after the
tap is turned on.

It's only for the odd non-dishwasher bit of washing up and for
cleaning surfaces etc. so we think a Redring MS6, 1.5kW 6 litre one
should be quite sufficient.

Our water pressure is within the MS6 specification so we don't need a
pressure reducing valve.

However we will need an expansion vessel as the cold tap for the sink
is (unsurprisingly) adjacent to the hot tap (well, it's a mixer). The
specified expansion vessel:-

https://www.fastlec.co.uk/87-783101-...83101-cwp.html

costs *more* than the water heater! That's really ridiculous.

I'm thinking of simply adding a loop of copper pipe to give the
required 1.7 metre length that's required to avoid the need for an
expansion vessel. 1.7 metres of copper pipe will cost a whole lot
less than £75!

Is this a sensible idea?

--
Chris Green
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