Always verify the individual model code on the compressor nameplate before installation

ensuring the circuit interrupts before thermal damage occurs

field technicians often trim these stainless steel probe rods to meet specific low-water cut-off elevations prescribed by the boiler manufacturer

this unit utilizes a 20-micron filtration pad to capture debris and desiccant fines before they reach the expansion valve

For contractors performing Armstrong furnace troubleshooting

Allanson 421-557 Transformer Els PW 17895 Always verify the individual modelThe Allanson 421 557 is a heavy duty oil burner ignition transformer engineered specifically for Arco and American Standard burners. This iron core transformer utilizes a 120V primary supply to deliver a consistent 10,000V secondary output at 23mA, ensuring a powerful arc for reliable burner ignition in demanding environments. Designed with a mid point ground configuration, the 421 557 features a high silicon steel core and large gauge copper windings