Mike PleziaInside service technician, Clark Associates · Commercial Equipment, HVAC, and Refrigeration professional

Combustion Analyzer: Your Furnace Safety Check

2 Oct 2026 · 1 min

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1:22

In this instructional monologue, the speaker explains why a combustion analyzer is indispensable for any thorough heating system tune‑up. By inserting the probe into the furnace flue, the device samples exhaust gases and reports carbon monoxide (CO), carbon dioxide (CO₂), flue‑gas temperature, and overall combustion efficiency. CO is highlighted as a poisonous gas, while CO₂ and temperature indicate how completely the fuel is burning and how much heat is being lost through the vent. The speaker stresses that visual inspection alone can miss dangerous conditions such as dirty burners, blocked vents, poor draft, or gas‑pressure issues, which the analyzer can detect before a crisis occurs. Practical guidance is given: follow the manufacturer’s procedure, allow the instrument to stabilize, record the readings, and investigate any out‑of‑spec results rather than guessing. The overall message is that combustion analysis is a safety check, not a sales pitch, and that sharing this knowledge helps keep others safe.

Chapters

Hey, are you new to the trades? Here's something you may not know about a combustion analyzer. A furnace can sound normal and still make unsafe flue gas. That is why a combustion analyzer belongs in every serious heating tune-up. You place its probe in the flue pipe, and it samples the gases leaving the furnace. The analyzer measures carbon monoxide, or CO, carbon dioxide, or CO2, Flue gas temperature, and combustion efficiency. CO is poisonous. CO2 and temperature help show how completely the fuel is burning and how much heat is leaving through the vent. Together, those numbers tell you whether the burners are burning cleanly and safely. A dirty burner, blocked vent, poor draft, or gas pressure problem may not be obvious by sight. The analyzer can catch a dangerous CO level before it becomes a crisis. Follow the manufacturer procedure, let the instrument stabilize, and record the readings. If results are outside the equipment specifications, do not guess— investigate and correct the cause. Measure what you can't see. Combustion analysis is a safety check, not an upsell. Now that you know, you can help someone else know.