D R A F T R E G U L AT O RS Everybody starts to head for the exit door, the chimney or venting
device (through a six inch pipe) and you reach this elbow and now you really have to struggle because you like to go in straight lines and there's this turn. (If you use 45 degree elbows you'll find you have better draft because they have less than half the resistance of 90 degree elbows.) You make it through the elbow and wham, an intersection!
Here's this tee, one way goes back to the room and the other goes to the exit, but it's dark and you can't tell which way is out. Unlike a valve or fitting there are no arrows on the outside to tell you which way to go. It's at this point that we face the old "path of least resistance" problem. Do you go out to the room or do you go out the door? Which door? (Remember the regulator is a door.) On top of that it requires no effort for you to travel in a straight line (unless it's over 18 inches long), but to make it through this tee is like traveling through another 38 feet of pipe, Figure 2. Man, are you getting tired. But, most of the molecules are
headed for the chimney so you go with them because you're a social guy, right? Although everybody is working hard to get out, it's tough and then whoof, the fan shuts off, oh-oh! Now it's which way to go again. The regulator and the room are
only 4 inches away, the top of the chimney is 35 feet, and so what do you do? Hey, if you sneak out the regulator who's gonna know? Well,
my little molecule, everyone will, because you smell! See, you're not a smell-free molecule of air anymore. Oh no, you've become a mol- ecule of flue gas and you smell just like the combustion process you just passed through whether it was oil, bioheat, kerosene or LPG, you stink, bad! But in addition because you're carrying that fuel residue with you, you also make lots of tracks and so you stain the regulator opening, Figure 3, and fall to the floor as soot. Bad little molecule! Although I've hopefully made you chuckle or even at least
smile, keep in mind that this is serious stuff, and doing it wrong can never be justified by just saying, "Well, it hasn't caused me any problems." Trust me, it all catches up to us, so be careful and do the job right every time. By the way, if you read the directions you will find that not only do all the people who make draft regulators not want you using the plumbers tee (except with atmospheric gas), but neither do the appliance manufacturers. By the way, we have more to say about draft regulators in our new book Venting (Conventional Gas & Oil Systems). l FON
See ya. George Lanthier is the owner of Firedragon Enterprises, a teaching, publishing and consulting firm. He is an industry trainer and the author of over 25 books on oilheating and HVAC subjects. He can be reached at 608 Moose Hill Road, Leicester, MA 01524. His phone is 508-421-3490, fax at 508-421-3477 and his web-site and chat room can be found at www.FiredragonEnt.com
www.fueloilnews.com | FUEL OIL NEWS | SEPTEMBER 2011 17
