BY GEORGE LANTHIER
Figure 2
that door will be the one at the top of the basement stairs.
The easiest way to test the smoke enclosure is to remove the doorknob lockset from the solid door and most come off very easily. With the lockset, Figure 2, removed you will have a big hole. Close the lockset hole off with a piece of cardboard and some tape and then punch a ¼” hole in the cardboard. Because of all of the tests that I’ ve done I have a piece of sheet metal that has a ½’ piece of Styrofoam on the back and I tape that down to the door. You can make up your own test plate the same way!
Now with the gauge and yourself outside of the room get the burner running. The gauge is now reading the smoke enclosure( room), and you must run the burner for at least 15 minutes to create at least one air change. Do what you have to do to make this happen but keep that burner running. By the way, with commercial and industrial jobs you may have to drill a steel fire door, so bring some fender washers and a ¼” x 1” bolt and nut with you.
Okay, so the burner’ s been running a while and the gauge is actually reading a negative draft like you were checking a chimney, not good! The higher that gauge climbs the less air you have, but it doesn’ t really matter because any reading other than zero is telling you that the burner is trying to suck your gauge through the door and you need to bring inlet draft in from someplace.
In 58 years, I’ ve only seen two cases where after the gauge read a negative it then went positive after pressurizing the room. That is an indication of a defective venting device and your chimney, powerventer or terminal must be checked right away for blockage. It’ s also when you think about it an indicator that the burner is trying to get out of the room, so be careful! Okay, so we’ ve beaten inlet draft to death, I think?
Now we’ re going to look at combustion draft and this is another area that the draft gauge is essential for. Good combustion draft must be maintained to have a great fire and burn all of the fuel prepared by the
24 MAY 2026 | FUEL OIL NEWS | www. fueloilnews. com