When draining system to replace taps should combi boiler be turned off?

[Mmcgar]

I need to replace the cold tap in my bathroom sink. Since I can't get the exact replacement tap I'll have to replace the hot aswell.

Should I turn the combi boiler off when I'm draining the hot tap down? I'm thinking that if I don't then as the water drains, the boiler will be trying to heat water that isn't there and this could be an issue?

 

[ianmcd]

just isolate the cold water inlet at the boiler and open the hot tap, boiler will be fine using the CH with the water isolated