Banging Pipes?

1. They checked the pitch, to see that the Condensed Steam, water, could Drain back to the Boiler. 

2. Then replaced a Radiator Steam Vent.

3. However It appeared the supply valve

3. However It appeared the supply valve had been leaking , WATER...

FROM SUPPLY STEAM???

4. Checked the Boiler guage glass, which should've been at half way but it seemed to be full, tough for the Boiler to generate steam, when FULL!!! 

 5. Additionally there was evidence that the Main Supply Vent had leaked.

6. More evidence the valve had been leaking for some time.

7. So, Shut off the Auto Feed, Drain down the boiler to 1/2 and fire it up. (mark the water level for future reference)