Nobody likes a chattering PSV. But do you know what causes PSV to chatter?
Chattering is the rapid, alternate opening and closing of PRV.
The resulting vibration may cause misalignment, valve seat damage, and if prolonged, can cause mechanical failure of valve internals and associated piping
Chatter may occur in either liquid or vapor services.
Reasons for chattering:

• Excessive pressure drop of PSV inlet line
• Excessive built-up back pressure
• Oversized valve
• Set pressure is equal to or very close to the operating pressure
• Multiple PSVs with the same pressure setting

Ways to avoid chattering:

• Avoid long pipe runs.
• Avoid bends.
•  Inlet line size must be at least equal to PSV inlet flange size.
• Discharge line diameter should be at least equal to PRV outlet flange size.
• Inlet piping should slope continuously upward from the vessel to avoid traps.

I hope this was useful to you. Please do share this with your friends.
Take care.
Ajay S. Satpute