Most common troubles with boiler safety valves are:
Chatter - Metallic hammering sound or vibratory noise. The reason being bent spindle, improper clearances, loose blow down rings, improper position of upper and / or lower adjusting ring position, excessive back- pressure etc.
Simmer - The first leakage of steam before the safety valve pops open, which allowed 1.5 to 2% popping pressure of the valve. Prolonged simmering maybe due to improper position of adjusting rings, distorted valve parts etc..
Leakage -Constant hissing sound. The reason being damages seating, defective parts, scale or foreign matter in the sealing surface, distortion due to waste steam pipe fitting, interference from easing gear and spindle etc..
Hang-up - Safety valves fail to re-seat. The reason being improper blow down adjustment, mechanical interference etc.
