Never let the pressure rise above 30 psi or the safety valve on the boiler will lift.
Depending on how a system is piped it may require bleeding with the circulator off or on.
Again, depending on how it is piped you may need to bleed each zone individually. Do the heat emitters (baseboards or radiators) have individual bleed valves?
System pressure when cold is usually about 12 psi. This may be a bit higher if it is a three or more level house.