On 17/08/2018 07:50, The Natural Philosopher wrote:
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...
That does rather depend on a number of factors. Normally the cold shut
off to the cylinder is situated right before its inlet control valve. So
once that is shut, its isolated from the rest of the cold water system.
However if you were relying on the main cold stop tap to the property,
then there may be an issue.
then the loo will allow air into the cold side of the systemÂ* and the
hot water will all come out.
Depends a bit on where the cylinder is. On the ground floor, there would
not be an issue since you would need a head of water above it to get
more hot out. So at most you could get a "pipe full". If its in the loft
then potentially you might get a bit more - but the moment air is drawn
into the cylinder, it will break any siphon action and stem the flow.
--
Cheers,
John.
/================================================== ===============\
| Internode Ltd -
http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/