Carrier HH12ZB170 Limit Switch and various System 1 modulating

and various System 1 modulating furnaces

304100 is the official manufacturer part number (MPN) for the Model F-26 gasket used across several legacy and modern M&M water feeders

Use a multimeter to check for continuity across the terminals when the system is cool

replacing the 071-03409-003 red spring restores the mechanical accuracy required for safe combustion

Does this connector require frequent lubrication

Carrier HH12ZB170 Limit Switch and various System 1 modulatingThe Carrier HH12ZB170 Limit Switch is a critical safety component designed for precise thermal monitoring in high efficiency furnace and air handling units. This OEM replacement limit switch features a fixed temperature range, engineered to open at 170F and automatically reset when temperatures drop to 130F. As an L170 40F thermal switch, it provides essential protection against heat exchanger overheating by interrupting the burner circuit if airflow