More on Draft

One of the greatest understatements of my life was when my first magazine editor 35 years ago asked me to “write on something simple, like draft.” Since then I’ve written several books and hundreds of articles containing millions of words for numerous magazines in several countries on nothing but draft, and let me tell you something, it’s not simple, but it is the most important piece of getting the perfect flame puzzle solved.

The basic draft principle is simple, but it’s taken me on quite an adventure and will lead to eventually another book called ‘Venting,” which is really a stand-alone non-fuel specific Volume Two of Advanced Residential Oilburners. 

I’ve seen guys spend hours, days, even years on a job playing with nozzle types, orifice sizing, oil pump and gas pressures, head adjustments and all kinds of stuff and still not get it right because they missed the most important point’the airflow is wrong.


Remember this quote from my books and seminars, ‘faulty draft conditions cause more flame and combustion problems than any other single factor.” That statement was first made in a manual on the installation of the low-pressure Williams Oil-O-Matic oilburner published in the 1930s, and it has never been more accurate than it is today. That’s what I’m talking about, brother; that’s what it is all about: gas or oil, wood-pellets or coal, anything!


It turns out that with today’s modern power burners (gas or oil) and heat exchangers if the airflow is not right, then nothing can be right. True, you have to get fuel to the combustion head, but that’s easy for most of us compared to the problem of getting the airflow right.


With most of the modulating-condensing gas boilers used today when you adjust the gas/air, you adjust the entire airflow and fuel mix. So in many cases as long as you’ve dialed in the right CO2 or O2 reading, the equipment does the rest.


Now as it turns out again, you probably don’t have that many problems with older units and most warm air furnaces and water heaters. These all tend to run with negative pressures at the breeching and over-the-fire; so the old golden rule of -.01 to -.03 inches of water column over the fire with -.02 to -.04 inches of water column in the breech is still working for you and should.


But I’m talking about the Cadillacs


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