Testo® 330-1 Combustion Analyzer & Easy Heat Software

Combustion Testing: ON a Viessman CT3-46 (Sealed Combustion)
Using a Testo® 330-1 combustion analyzer and Easy Heat™  software, observed the combustion over time in high and low fire. The stability of the combustion is being affected by changes in CAZ (Combustion Air Zone) pressure due to intermittent loss of draft through the appliance due to the negative fluctuating mechanical room pressures. This was observed during the draft readings, CO readings, stack temperatures and O2 readings. Due to the instability of the combustion process, both boilers will require re-commissioning after the ventilation air issues are resolved. Although no CO was produced during operation as the technician left the boiler, changes in building pressures could result in CO formation and pose grave danger to the building occupants. 

Using a Combustion Analyzer to Test Heat Exchanger Integrity: http://hvacprotech.forumwise.com/hvacprotech-thread4956.html