HVAC Refrigeration Guide — Ignition Lockout

Gas Furnace Ignition Lockouts: Single-Stage vs. Staged Systems

Sep 16, 2026

Learn how to diagnose gas furnace ignition lockouts across conventional single-stage and staged or modulating systems. This guide covers igniters, flame sensors, pressure-switch interlocks, fault codes, and the testing sequence that helps prevent unnecessary parts swaps.

Tags: condensing furnace, flame sensor, furnace repair, gas furnace, heating systems, hot surface igniter, HVAC diagnostics, ignition lockout

Armstrong Furnace LED Flash Codes: Diagnose Before You Replace

Aug 02, 2026

Armstrong furnace flashing 2, 3, or 7? Count the LED before you open anything. This guide maps every flash code to its likely cause — pressure switch, inducer motor, or ignition electrode — and shows you how to confirm the right part before ordering.

Tags: 27X92, ALPKT516-4, Armstrong Furnace, Flash Codes, Furnace Fault Codes, Furnace Troubleshooting, Heat Strip, HVAC Repair, Ignition Lockout, Inducer Motor, LP Conversion, Pressure Switch, R100684-04, R101523-01, R45688-001