Lochinvar & A.O. Smith 100167821 Board R-407C but you must never go

but you must never go lower than the original system specification

Using these orifices in lower BTU units will cause over-firing and potential heat exchanger damage

such as de-energizing crankcase heaters or triggering alarm circuits when the main contactor is engaged

clogged condensate lines

then increasing the setpoint according to the equipment's normal operating vibration levels plus a safety margin

Lochinvar & A.O. Smith 100167821 Board R-407C but you must never goThe Lochinvar & A. O. Smith 100167821 Integrated Control Board is a critical OEM component designed for high efficiency gas fired boilers and water heaters. As a direct replacement furnace circuit board, this module manages essential system sequences, including hot surface ignition, flame rectification, and manifold gas valve actuation. It serves as the central processing hub, utilizing real time sensor data to modulate thermal output and optimize