How Is Carbon Monoxide Testing Done for HVAC Systems in Vancouver?
Published: July 21, 2026 — CANRO Heating & Cooling — Greater Vancouver, BC
The Testing Procedure
A technician uses a digital combustion analyzer to measure CO in the exhaust flue gases. The analyzer probe is inserted into a test port on the flue pipe (or held at the flue opening). The analyzer measures: oxygen (O2), carbon dioxide (CO2), carbon monoxide (CO), and flue gas temperature. These measurements calculate combustion efficiency.
Acceptable CO Levels
Safe levels: less than 100 PPM air-free for gas furnaces and boilers. Good: less than 50 PPM. Excellent: less than 25 PPM. Action level: above 100 PPM — the appliance needs immediate service and should be turned off. Above 400 PPM — the appliance is producing hazardous levels of CO and should not be operated until repaired.
When to Test
CO testing should be done: during annual furnace or boiler maintenance, after any gas appliance service or repair, if you have CO poisoning symptoms (headache, nausea), if your CO detector has alarmed, after installing a new gas appliance, or if you notice soot around the burner area. Annual testing is the minimum for safety.