For contractors performing Armstrong furnace troubleshooting

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

while the 5-screw low-voltage terminal board provides a clean

OEM Compatibility: Direct fit for York

Built with high-grade materials to withstand extreme thermal stress

Allanson 421-557 Transformer Els PW 17895 For contractors performing Armstrong furnaceThe 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