On 17/08/18 00:28, John Rumm wrote:
On 16/08/2018 22:19, Michael Chare wrote:
On 16/08/2018 20:48, Chris B wrote:
On 16/08/2018 20:44, Tim+ wrote:
The hot water system is just a €śthrough the boiler/heat exchanger€ť
system
so just turn off cold inlet to boiler, change washer, job done.
No, its the 185 lt of hot water in the pressurised cylinder I'm
worried about......
If you turn off the mains, does any water come out of the hot tap?
With an unvented cylinder there is another pressure vessel that copes
with the expansion of the DHW as it heats. Shown as item 10 he
http://wiki.diyfaq.org.uk/index.php/...ted_cylinde r
Once the cold feed to the cylinder is shut off, you will still get
several litres of hot water out. However let it run and that will reduce
to nothing as the pressure vessel de-pressurises.
Until someone flushes a loo...
then the loo will allow air into the cold side of the system and the
hot water will all come out.
It maybe that to get water out of the tank you have to let air in by
loosening a compression joint at the highest point in the pipe work
between the cold water feed to the house and the hot water tank.
Turning on a cold tap might also let the hot water out.
There should be no need to drain the cylinder itself. Once there is no
mains pressure to push the hot water out of the top of it, no hot water
will flow.
--
Religion is regarded by the common people as true, by the wise as
foolish, and by the rulers as useful.
(Seneca the Younger, 65 AD)