This OEM-spec M&M 304100 is fully compatible with the McDonnell & Miller Series 221

this OEM York replacement part is engineered to withstand the thermal stress and acidic environment typical of high-efficiency heating cycles

It utilizes the same wiring terminals and mounting footprint for efficient field replacement

System Protection: Prevents gas valve activation under restricted flue or intake conditions

While some kits may include mounting hardware

Heil Quaker ICP 1177023 Transformer 320720-756 This OEM-spec M&M 304100 isWhen you are dealing with high voltage industrial HVAC systems, the Heil Quaker ICP 1177023 Transformer is a critical step down transformer for maintaining control circuit integrity. This heavy duty 460V to 230V transformer is engineered for precision power conversion, featuring a primary voltage of 460V and a secondary output of 230V. With a substantial 1564VA capacity, it provides the robust power distribution required for larger commercial units