Combustion Analysis Across Light-Off, Steady State, and Shutdown with Tyler Nelson - Part 1

In this episode of HVAC Know It All, host Gary McCreadie talks with Tyler Nelson, Master HVACR, HVAC Sales Manager & Trainer - Americas at Seitron Americas Inc., about testing combustion at light-off, steady state, and shutdown. They examine what each phase can reveal about burner operation, heat exchanger integrity, and fuel delivery. Technicians will learn why steady-state readings alone can miss diagnostic clues and how analyzer protection affects testing practices.

Tyler wrote Combustion Analysis: The Essentials and recently joined a collaborative team of trainers at Seitron Americas Inc. His teaching connects analyzer readings to a diagnostic thought process: what a technician observes, what it might mean, and what to check next. That approach also informs his use of multiple tests when evaluating a suspected heat exchanger breach.

Key Takeaways How testing at light-off, steady state, and shutdown reveals different operating characteristics that steady-state testing alone can miss.

Why Nelson uses CO air-free readings to evaluate combustion and distinguishes light-off thresholds from steady-state thresholds.

How monitoring oxygen after the blower starts can help identify a suspected heat exchanger breach as part of a broader verification process.

How shutdown readings can reveal clues to a leaking gas valve, residual oil, or a secondary heat exchanger drainage problem.

Why light-off testing requires close attention to analyzer sensor protection, and why temporarily closed supply registers must be reopened after static-pressure testing.

Key Timestamps 00:00 - Factory Direct Filters Ad

00:42 - Guest and Episode Introduction

02:24 – Defining light-off, steady state, and shutdown

09:20 – CO air-free readings and combustion evaluation thresholds

15:58 – Analyzer protection and focused attention during light-off testing