Kunkle 6254 Safety Valve — 4″ 250# Flange x 4″ FNPT, L Orifice (Steam ASME Section IV, Metal Seat)

The Kunkle 6254 is the ASME Section IV version of the 6252, certified for low pressure steam heating boilers. It is the same heavy-duty cast iron valve with a stainless steel semi-nozzle, trim and disc, dual control rings and a bolted bonnet — but it is built and stamped for a single set pressure of 15 PSI, which is not field adjustable. This 4″ 250# Flange x 4″ FNPT variant — L orifice, 3.138 in² — relieves 4921 lb/h of steam at that setting, carrying the ASME Section IV and XIII ‘HV’ stamp and National Board certification. Temperature range -20°F to 406°F. Per ASME, code valves with a cast iron A126 body may not be used in lethal or flammable service. If you need an adjustable set pressure, specify the 6252 instead.

↓ Kunkle 6252/6254 Series Datasheet (PDF)