Understanding Your 2-Stage Furnace: Pressure Adjustments Explained
In this short technical dialogue, the speakers walk through how a two‑stage gas furnace operates and how to verify that its gas‑valve staging is functioning correctly. They explain that the furnace runs on a low‑stage first, which operates at a lower pressure, and then switches to a high‑stage that delivers the true system pressure. To confirm proper staging, the unit must be allowed about a minute to transition. The expected pressure range for proper operation is around 3.4–3.5 inches of water column. Adjustments are only warranted when the measured pressure deviates by roughly two inches or more from this target. Finally, they stress the importance of checking both inlet and outlet pressures to ensure each stage is performing as intended.
