BY GEORGE LANTHIER

Since 1978 I’ ve written a lot of articles on draft and combustion, so many in fact they became the basis for one of my books,‘ COMBUSTION & Oil Burning Equipment’ that is now known as“ Advanced Residential Oilburners”. Although oilheat service technicians have to know a lot of things from controls to systems to metal working and even some carpentry to get the job done we sometimes forget that the most important job we are supposed to be doing is keeping the home fires of oilheat burning. Oh yeah, and you’ re supposed to keep those fires burning at true zero smoke, not trace. This an updated article from 2008, I hope you enjoy it.

After doing this for the time I have and teaching it for a while it still amazes me just how confused we get over some basic principles and so I’ m going to start at the beginning, square one. Draft science has not changed since day one, but boy, oh

WHY RISK YOUR FIRST-CLASS IMAGE WITH SECOND-RATE EQUIPMENT?

You ' ve worked too hard earning your customers ' trustto have unpredictable equipment performance trip you up. Nobody understands that like H & H. Our custom truck bodies are designed with field work in mind. We build them one at a time from the most rugged, high-quality materials and components available. No corners cut, no details overlooked. As a result, an H & H truck body won ' t let you down on the job. You get efficient, affordable, dependable performance, year after year, so your customers get the prompt, effective service they expect- every time.

Call: 800-551-9341 E-mail: info @ hhsalescompany. com

L.a�,..._.,. SALES

�r'I COMPANY, INC.

CUSTOM TRUCK BODIES AND MANUFACTURING

16339 Lima Rd.,., P.. O. Box 686 • Huntertown, IN 46748--0-0 686 Phone: 260-637-31TT • 800-551-9341 • FAX: 260-637-6880 E-mail: inlocthhsalescompany.. com • Web: www.. hhsalescompany.. com

NIEA

� boy, has the technology. The area that we must know the most about and really understand completely is draft. Draft in my opinion falls into three areas of concern, inlet draft, combustion draft and venting draft. You may notice I didn’ t use the term air. Well, I shouldn’ t have to. When someone says draft, you should immediately think of air, because that’ s all there is to it.

The American Society of Heating, Refrigerating and Airconditioning Engineers( ASHRAE) define draft as“ a column of air in an enclosed space” and a dictionary will give you the same definition. So, why do so many of us think that draft only begins, well, wherever?

The first thing to do is picture yourself as draft or air and that you are outside the structure. Your job is to get in, mix with the oil, do a few other little jobs and get back outside again. Have you got it? Let’ s go exploring!

I first coined the term‘ inlet draft’ while teaching basic students in 1975. I used it to try to show that there is only one current of air( draft) from start to finish in the combustion process. It must be there and it must be‘ balanced’. Look at the simple drawing in Figure 1. Draft is on a seesaw, if it has enough coming in it will balance, if it doesn’ t, well, do you get it?

Anyway, let’ s get going and look at how this is supposed to work, here goes;

First, you must travel into the burner as inlet draft( inlet or combustion air). When you think about it this has a lot of names and that’ s really weird for something you can’ t even see. This is even more amazing when you look at some of the

Figure 1

Figure 2

things we do to get it where we need it. Remember you started outside, so you must get in. That means through tiny cracks and crevices around doors, windows and the foundation sills, that’ s called“ infiltration” or“ crack”. If you’ re lucky there are enough spaces to go through, if not, well …

Okay, so you’ ve made it into the burner room. Now you have to get into the burner, Figure 2, move across the fan and travel down the air tube. Remember, all this time you’ re still inlet draft, but parts of you are spun off through the combustion components of the burner and now even your own mother would be impressed because you’ ve acquired names like primary air, secondary air and tertiary air, very impressive! Instantly at the combustion head you become combustion draft as you mix with the fuel and become part of the flame process and start to find

26 MARCH 2026 | FUEL OIL NEWS | www. fueloilnews. com