On Mon, 09 Jan 2006 16:38:58 +0000, Steve S wrote:

Now that my heating controller is nearly done I've been using it to collect
data. Some of it is quite surprising, at least to me.

We have a ~25 year old 120L HW cylinder with foam insulation. Over a period
of 6 hours with no heat input (and just a couple of handwashes) the
temperature dropped from 61.5 C to 56.5 C. Measurements have a resolution of
0.1C. According to my calculations that represents a loss of ~2.5
megajoules, which over 6 hours is an average of ~115W.

I daresay modern cylinders could do a lot better than this, but somehow I
was expecting the losses to be higher.

I beleive that a modern Part-L compliant cylinder would do a bit better
but these numbers are not very far out.

To improve this, make sure that all the hot pipework is insulated the
losses from 1m of HW pipework is about 20W

The hand basin uses may have taken out a fair bit from the cylinder even
if you did not wait for the WH to come through.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
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