On 2016-11-29, NY wrote:

"Adam Funk" wrote in message
...
On 2016-11-26, newshound wrote:

Don't Combis normally have a tap on the DHW outlet? That said, turning
off the main at the inlet (or the stop tap) is all that is needed. It's
perfectly safe to leave the CH running with the mains stop tap turned
off.

Thanks, everybody. I do remember that her boiler has separate
controls for turning the CH & hot water on & off.

Er, are you talking about turning off the heating aspect of the boiler or
turning off the water supply? I thought you were talking about replacing a
tap washer, which mean tuning off the water supply to that tap (either by
closing a stop vale of by turning off the rising main). Turning off the hot
water control at the boiler would simply ensure the water to the tap was
cold rather than hot - it wouldn't turn off the water flow itself. Maybe
I've misunderstood your phrase "her boiler has separate controls for turning
the CH & hot water on & off" - maybe you are referring to a tap rather than
a control switch. Or maybe your system has motorised stop valves, which
*would* mean that when HW is turned off at the boiler controller, water flow
was turned off.

What I mean is this (just to clear):

1. turn the boiler control for hot water off;
2. turn off the main stopcock;
3. cut into the pipes and add service valves for the hot & cold taps
(might as well, in case the cold one goes next);
4. turn the main water back on & check that the service valves don't
leak;
5. turn the boiler control for hot water back on (so she can use hot
water at the other sinks);
6. fix the dodgy tap as necessary, reconnect, & turn the new service
valves on.