Have Burnham boiler with 5 zones, 4 heat, each with circulator. Hearing air in a couple of the circuits.
Bled air in one, now hear air in others. There is a circulator pump for each circuit/zone on the input side of the boiler. Ahead of each pump is a shutoff valve and a "faucet" for bleeding water. There are also shutoffs for each zone on the output side of boiler. A cold water feed valve is set to open. I bled air by first shutting off the electrical switch and then closing the input shutoff valve and opening the bleed faucet for a zone. I DID NOT close any other zones when I did this. Should I have shut off ALL input valves while bleeding one zone? Thanks, David