In March of 2008, Fuel Oil News published one of my articles called “Update Procedures.” It had to do with the cold-starting of boilers and the effect that process has on heating systems and chimneys. I’m not going to go over all of it again, if you want to read the full article you can find it in Fuel Oil News archives on-line.
I mentioned back then the mess high-efficiency equipment was making of chimneys and here’s that part of the article again:
“Venting is tough except maybe in the dead of winter because the chimney cools during cycles and there is little to no thermal draft present on start-up. Tight combustion heads have helped with off-cycle losses over older oilburners, but they also do their job and reduce the flow of air through the chimney causing the oilburner to have to reheat the chimney every cycle increasing condensation. In the warmer weather, cold-start boilers can wreak havoc with service again due to draft problems.
“Cold-start, high efficiency boilers, in my opinion, also lead to a lot of damage being done to chimneys and masonry chimney liners that is called spalling… In addition, low temperatures in the flue may never properly heat up and then condense on the top of the chimney, causing the condensation of flue gases and the resultant freezing of the condensation.
“Finally, on the subject of flue gases I am beginning to believe that our industry standard of maintaining a minimum of 350°F Gross and 285°F Net stack temperature is not adequate for most chimneys in the United States and Canada. These chimneys are for the most part too tall, too big and don’t warm up quick enough. In addition, the 350°F Gross is normally with a maximum of 10 feet of fluepipe. In many cases flue pipes are longer and just add to the cooling process along with improperly installed and simply not needed draft regulators. I am now recommending that we maintain a minimum of 400°F Gross at the breeching and that we run a slightly higher temperature to prevent problems and enhance operation. If you line the chimney with stainless, fine; 350°F just may do it, but if the chimney is masonry and masonry lined I would go to 400°F.”
I mentioned the pictures that I had, but couldn’t release at the time due to litigation. I want you to see these pictures not only for the effects of doing it wrong, but also the results. Figure 1 shows an improperly installed draft regulator installed in a fashion known as a ‘plumber’s tee’. As we’ve discussed more than once here and in my books, the “plumbers tee” is O.K. for atmospheric gas, but not for any type of powerburner, oil or gas. Figure 2 shows icing in the chimney. It is these ice formations, caused by low stack temperatures, which give us the cleansing effect and create spalling. Finally, in Figure 3, the blocked chimney base that finally caused the CO (Carbon Monoxide) to release into the home. This incident left one person brain dead and another impaired.
Again, as I said in that article:
“Many of us do things because we were taught to do them the way the guy who taught us did them. In most cases he was taught by a guy in 1938 who was taught to do it following the anthem ‘But we always did it that way.’ Technology has progressed a long way and yet many in this industry think that our outdated traditions make more sense than following the manufacturer’s recommendations and that won’t hold up in court because it just doesn’t make sense.”
I encourage you to find out more about combustion and chimneys since one has already defined our reputation with many customers and the other soon will. Nobody knows it all and can’t, but we should know these two subjects better than all of the others we deal with as technicians. There’s always a better way, so let’s try to meet each other in class before we meet each other in court.
*George Lanthier is the owner of Firedragon Enterprises, a teaching, publishing and consulting firm. His website is www.FiredragonEnt.com and he can be reached at 508-421-3490 or at the Firedragon Academy, 608 Moose Hill Rd., Leicester, MA 01524