Carbon Monoxide Diagnosis & Combustion Safety

A carbon monoxide problem is the one chimney hazard you can't see, smell, or afford to guess about. When a CO detector alarms, when a flame burns wrong, or when a tight home starves an appliance of air, the difference between a real fix and a dangerous reassurance is whether someone measured it. Prime Chimney Experts diagnoses CO and combustion-spillage problems with instruments — combustion analyzers, draft gauges, and worst-case depressurization testing — and corrects the source, then verifies the fix by re-reading the numbers.

CO comes from incomplete combustion and from flue gases spilling into the house instead of going up the chimney, and finding the cause takes measurement, not intuition. We probe the appliance with a combustion analyzer to read CO, O2, and stack temperature, measure draft in inches of water column at the draft hood, and run a worst-case depressurization (BPI-style) test — closing doors and running exhaust fans to put the house at its most negative — to see whether the flue still drafts or spills under real-world conditions. A tight, exhaust-heavy modern home can pull combustion gases back down a chimney that tests fine on a calm day; only worst-case testing catches it.

Once we know the mechanism, we correct it at the source. If the appliance is mis-tuned, we tune the burner into spec. If the flue is spilling because of a draft problem, we fix the draft — resizing, a draft-inducer, or a height correction. If the house is depressurizing the combustion zone, we add combustion air or seal return leaks. If an oversized common flue is orphaning a lone water heater after a furnace upgrade, we re-line it to the correct size. The fix matches the actual finding — not a parts-swap guess.

The non-negotiable final step is re-verification. After the correction, we re-run the combustion and draft readings and re-test under worst-case conditions to confirm CO is in spec and the flue draws without spilling, and we document the before-and-after numbers. We also address detection: standard UL-2034 alarms only sound at 70 ppm and ignore the chronic 5–30 ppm exposure that causes long-term harm, so where appropriate we place low-level (7-ppm) monitors near combustion appliances and sleeping areas and can wire a spillage interlock that shuts an appliance down on backdraft.