Welcome! Here are the website rules, as well as some tips for using this forum.
If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
I dont usually work on residential furnaces (oil) but circumstances forced me to. It is a new Armstrong 85% forced air with Beckett NX burner.
I bought a smoke pump for the job and did an “as found” test several times and came up with zero on the scale then a combustion analysis which yielded bad numbers. The furnace was grossly sooted up. After cleaning soot out of furnace and flue and tuning burner, i did another several smoke tests and was still a zero on the scale.
Yet, the filter on my test probe was completely blackened during tests/tuning. Concerned, I replaced filter and left probe with analyzer on in flue all day while the furnace did it’s normal thing and the filter was in the 0-1 scale range. closer to zero. Why didnt I pick anything up with the smoke pump during “as found “ tests?