The power stroke timing varies by load

maintaining stable liquid injection from full load down to 10% capacity

ensuring the unit remains virtually unaffected by ambient temperature fluctuations around the control body

the control module likely requires replacement

This HVAC blower switch is a direct-fit solution for maintaining the combustion chamber efficiency and protecting the motor from short-cycling

York S1-331-09150-000 Control Board Kit THPU32HP7Y The power stroke timing variesThe York S1 331 09150 000 Control Board Kit is a critical OEM replacement part designed for Simplicity 1A 2 4 stage HVAC systems. This dual stage control board acts as the central intelligence for your rooftop or split system unit, managing the precise sequencing of ignition, gas valve regulation, and flame sensing. As a direct replacement for legacy model S1 03109150000, this kit ensures full HVAC system compatibility with residential and commercial