"Sticking up for Paul
"any and all adjustments to a combustion appliance should only be carried out by a trained trade person."
I don't think Paul said anything about making adjustments "do combustion safety and gas leak…"
Combustion Appliance Zone Testing (CAZ) Made Easy (March 24, 2016)
-Adapting to the new BPI standard
-RESNET testing requirements
-NFPA testing requirements
-Best practices for best results