Lennox 78H74 Limit Switch 322838-753 Always verify the model and

Always verify the model and serial number on the furnace rating plate before installation to ensure exact furnace part compatibility

but you should verify compatibility with specific corrosive chemicals before installation

preventing catastrophic shell and tube damage

Can I program custom parameters on this board

Because the actuator can be installed or replaced without draining the system or using tools

Lennox 78H74 Limit Switch 322838-753 Always verify the model andThe Lennox 78H74 is a critical OEM L185F limit switch designed for precision thermal protection in residential and commercial Lennox heating systems. As a primary safety control, this high limit switch monitors internal heat exchanger temperatures and is engineered to open the electrical circuit if the ambient temperature reaches the L185F set point. This rapid response prevents internal overheating and ensures the system operates within safe HVAC