Recently I moved to a house fitted with a Glow-worm Xtrafast 120
Combination Boiler. There is a small central heating water leak causing
a pressure fall. I need to detach the half inch pipe at an upstairs
radiator and remove and replace the olive. I suspect the olive is
trapped slightly beyond the end of the pipe. Is it feasible to close
the radiator valves at both ends, switch off the power supply to the
boiler, shut off the cold water supply and drain downstairs until the
pipe leading to the radiator is empty? Would I need to relieve the
water pressure and how? What else would I need to do before I restart
the system? My previous home had a traditional hot water/heating
system. I would be extremely grateful for any advice for solving this
problem.

"gjf"  wrote in message
news:1111938368.281331.265400@g14g2000cwa.googlegroups.com...

> Recently I moved to a house fitted with a Glow-worm Xtrafast 120
> Combination Boiler. There is a small central heating water leak causing
> a pressure fall. I need to detach the half inch pipe at an upstairs
> radiator and remove and replace the olive. I suspect the olive is
> trapped slightly beyond the end of the pipe. Is it feasible to close
> the radiator valves at both ends, switch off the power supply to the
> boiler, shut off the cold water supply and drain downstairs until the
> pipe leading to the radiator is empty? Would I need to relieve the
> water pressure and how? What else would I need to do before I restart
> the system? My previous home had a traditional hot water/heating
> system. I would be extremely grateful for any advice for solving this
> problem.
>


There is no need to turn off the cold water supply when draining a combi.
All you need to do is OPEN both sides of the radiator you want to work on
and drain the water from the CH system. If you are working upstairs then you
only need to drain the top half of the system. Put some inhibitor in before
you refill the system and after bleeding the air out the job is done.

Adam

Many thanks for the reply Adam. I'll do it the way you suggest.