How do you bleed a peerless boiler?

You willl have a valve that separates the (heated) return from the (heated) supply. Make sure your system is off; shut this valve. Turn off or shut valves to all zones except one. Turn on (city or...

Blow down steam boilers YES Bleed hydronic boilers NO

Yes you can bleed a combi boiler. You do just the same as with a conventional boiler. However, the pressure will drop in your system, so you simply need to adjust it using the little tap (usually...

open then close it

There is a key similar to those on radiators on the boilers than can be turned round with an adjustable wrench etc.