When troubleshooting via the Navigator or Service Tool

Inspect the jacket for cracks or burn marks and verify continuity with a multimeter

verify that your manifold pressure aligns with the unit's rating plate to ensure the modulating control logic communicates correctly with the burner circuit

While the valve regulates flow in the cooling cycle

Resideo Q4100C9042 Hot Surface Ignitor R-448A When troubleshooting via the NavigatorThe Resideo Q4100C9042 Hot Surface Ignitor is a heavy duty 120V silicon carbide replacement designed for high performance ignition in gas fired furnaces and boilers. This HVAC furnace ignitor serves as a robust field service solution, engineered to withstand high operating temperatures with a 392F temperature rating. It features a standard mounting configuration with a rib on the right edge and a 5. 5 inch lead length, ensuring compatibility with