I recently took over a 3 story building that is currently heated by a hot water boiler with one pump. The mains run down the first floor hallway ceiling and takeoff for all floors. The complaint is banging pipes which I observed firsthand the copper fin baseboard shaking and banging. Over the last year about 20 of the 30 units have installed new fast closing zone valves. The noise is worse at the far end of the hallway. Could a end of the line bypass eliminate this problem. It seems as the majority of the zonevalves are closed the last ones to do so cause the banging. Any thoughts would be appreciated.
Look at installing a variable frequency drive, get a hold of your local pump rep. B&G, Taco, they should be able to help you select what you need. vfd,sensor etc. easier than piping in a diverting valve.
And if there is a flow control on the system to stop gravity circulation, check to see if there is a Flow Control Valve at the boiler. If they had one, and they installed zone valves, they can isolate the expansion devices from the system. You may also need more expansion capabilities or have an expansion tank that needs to be drained. If there is a flow control valve, open it. You don't need it now.
As stated, you really need a variable speed circulator. The circulator is too big for the application when many of the zone valves are closed.