how to change rad valves on combi system without draining do

[mike7920]

How do i change a radiator valve on a combi boiler system without having to drain the entire system ? I know the plumber i usually use can do this but i don't know what he does

 

[bengasman]

I wouldn't recommend trying it if you don't have the dexterity and experience that a plumber has. It saves you 10 or 15 minutes if it works, but can make an awful mess and waterdamage if it goes wrong.

 

[Deleted member 105431]

just do it live, it'll be fine.

 

[holty]

freeze the pipe work.i take it you have a sealed system.and before anyone says.yes you can have a combi on open vent.

 

[mike7920]

thanks for the speedy replies guys. holty - i do have a sealed system, and dangermouse 46- i have thought about doing it live but i definitely dont have the dexterity or confidence for that

 

[namsag]

Depending on which boiler you have you can either turn off the flow and return isolating valves or screw down the caps on any auto air vents. release the pressure and it should vacum up very quickly and bobs your uncle