as long as the controller is configured to accept a 10k ohm Type II NTC thermistor curve

forcing a manual inspection of the furnace before the system can resume operation

providing greater flexibility for field modifications

frequent tripping usually indicates restricted airflow due to a dirty filter

the Intermatic K4221C incorporates a built-in 30-to-90-second time delay feature

Robertshaw 41-403 Hot Surface Ignitor as long as the controllerThe Robertshaw 41 403 Hot Surface Ignitor (271M) is a heavy duty silicon carbide igniter designed for consistent ignition in 120V AC heating systems. As a veteran grade furnace replacement part, this unit features high purity recrystallized silicon carbide construction (Crystar), providing the structural integrity needed for demanding cycles in boilers, rooftop units, and infrared burners. It serves as the direct Robertshaw 41 403 cross reference for