Which Weil McLain models use these 12-amp fuses

or if you hear a chattering sound

Reliable Sealing: Features a rotating Buna-N ball plug and EPDM O-rings for tight shut-off and resistance to common hydronic additives

and internal system debris

this AC current transducer allows for installation without disconnecting the primary conductor

Armstrong International B1669-4 Pressure Change Assembly Els PW 17895 Which Weil McLain models useThe Armstrong International B1669 4 Pressure Change Assembly is a precision engineered internal component designed to restore the peak performance of your steam system. Featuring a 1 8" orifice, this assembly is vital for maintaining the mechanical integrity and discharge capacity of inverted bucket steam traps. It is fully compatible with a wide range of Armstrong models, including the 211, 310, 800, 811, TVS 811, 880, 881, 981, and EM Series.