On Jul 17, 7:15 pm, Matty F wrote:
On Jul 17, 5:05 am, PeterC wrote:



On Thu, 16 Jul 2009 05:33:36 -0700 (PDT), Matty F wrote:
On Jul 17, 12:08 am, PeterC wrote:
On Thu, 16 Jul 2009 09:32:27 +0100 (BST), Dave Liquorice wrote:
On Wed, 15 Jul 2009 23:19:15 -0700 (PDT), Matty F wrote:

With the stopcock "off", after running a tap for a few minutes, the
water gets decidedly warm. This is quite likely to be backflow from
the solar-heated hot water cylinder on the roof.

With the stopcock "on" does the water run warm after a similar amount
fo time? If not then it indicates that the stopcock is working and
there is flow from the solar tank.

I'll try that tomorrow. The stopcock is some 50 metres from the
building so it takes a while to try out ideas.

If the distance from the wooden tank isn't too much for the time to warm
water flowing, surely the water in it could flow warm if the sun had heated
the contents.

It's the middle of winter here and the water in the wooden tank is
definitely cold. I tested the shower and it is comfortably warm.

Ah, sorry - not thinking upside down.

I now think that it's the non-return valve that isn't working and the
stop-cock is working OK.
The shower hot water is taken from the top of the hot water tank.
With the stop-cock open we get hot water from the shower.
With the stop-cock closed there is no hot water from the shower.
Therefore the stop-cock must be working OK.
I'll find out when the non-return valve is fixed. There should then be
no water at all from the other taps when the stop-cock is closed.

Fixed it today. The non-return valve was not working. The stopcock is
working perfectly.
When the non-return valve was faulty, if any tap was turned on, that
allowed water to drain from the hot water tank, thus water did not
circulate through the solar water heater.