Thanks to everyone for their replies.
Tremolo -- To answer your question, the system is in service all the time. There are times when some process units are down for maintenance and thus there is less flow in the system due to reduced steam load. This does change the dynamics of the hammering...
In our plant there has been excessive hammer and vibration experienced in a 16" common condensate return header which discharges into the top of an open atmospheric condensate tank. Various condensate streams from process units are returned into the common 16" header. The streams are flashed at...