Allanson 421-557 Transformer 30067439-890 ensure you have the standard

ensure you have the standard Honeywell pneumatic mounting hardware on hand

check for continuity across the 24V heater pins (the bottom terminals)

1-inch window and a removable

Built for veteran contractors

Industrial Durability: Built to withstand the high-vibration environment typical of rooftop units and large-scale HVAC mechanical controls

Allanson 421-557 Transformer 30067439-890 ensure you have the standardThe 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