Lennox 86K37 Actuator THPU32HP7Y the control module is the

the control module is the likely culprit

With a dedicated 180-240F temperature range and a fixed 15-degree Fahrenheit differential

This is common in high-efficiency condensing furnaces if the secondary heat exchanger is leaking or if the combustion air contains corrosive vapors

compatibility rests on the specific wiring schematic of your PDH unit

Direct Replacement: Seamlessly replaces H91DA-1 models with an updated electrical connection

Lennox 86K37 Actuator THPU32HP7Y the control module is theThe Lennox 86K37 Actuator is a high torque, spring return motorized solution designed for precise regulation in commercial and residential HVAC systems. Identified by the manufacturer model MS7110K2006, this 24V power driven component delivers a robust 88 lb in (10 Nm) of torque, ensuring reliable damper and valve positioning even in demanding high static environments. As a veteran grade OEM replacement actuator, it provides a direct field swap for