Exhaust flue set screw

[Bunny Laroche]

Hello, there is a small port on our Westinghouse 80k BTUh boiler's exhaust port that has a sealed plastic set screw that does in fact unscrew all the way out, exposing a small hole in the exhaust pipe immediately above the boiler. Is this small exposed hole intended as a convenient point where a combustion analysis can be measured after the boiler has its gas turned on and is fire up?

 

[NY_Rob]

Yes, that's the test port for a combustion analyzer.