BY GEORGE LANTHIER

I have been teaching heating subjects for a while now. It started in 1973 in the US Air Force Reserve and then also included teaching at the old NEFI school in Cambridge and Watertown, Massachusetts. Teaching basic and advanced always comes back to where to start on a call and in my case the first thing that pops into my head is,“ What changed?” Maybe it’ s a very basic call and the most common problem is a switch is off – also known as an“ open limit.” In Massachusetts and other states that means something is keeping the burner from running. So, let’ s start at the beginning and find out what it is( Figure 1).

Let me give you a couple of my personal favorites as other examples. Nice Saturday in the Spring and my shift is almost over. Just one call so far, an“ out of oil,” the number two most common problem. What changed? No oil in the tank.

In the afternoon another call comes in,“ overheating.” Upon arrival at a two-story, two-family home, the customer tells me,“ I can’ t shut the burner off except through the‘ customer switch’ or the‘ serviceman’ s switch.’ The thermostat does nothing.”( Figure 1.)

I get the burner running again and the thermostat circuit is“ out of control.” I try even disconnecting the wires and when I remove them in the basement the burner goes off. Hmmm! So, I ask the customer,“ Did you do anything today?” He says,“ Nope, not me. But the guy on the first floor was banging on something.” So, I’ m off to interview the first-floor tenant because he changed something.

He tells us that the banging was from just hanging a picture on the wall in his dining room right below the second-floor thermostat. We take the picture down and get the second-floor burner running again. As soon as I pull the nail the burner goes off. What the hell are the odds of this guy punching through the thermostat wire? Pretty good, evidently. We move the nail an inch away and everything goes back to normal. We corrected“ the change.”

Another one in the category of“ something changed” is very common. Had it happen dozens of times. Customers complaint is“ excessive oil consumption.” This could be very serious because“ the change” could be a punctured underground line. Above-ground tank leaks are pretty easy to find as are leaks

Figure 1

Figure 2

at or around the burner, but underground lines are a whole other problem. I’ m not going to waste my time on explaining the benefits of sleeved or coated lines and osv’ s. You either get it, or you don’ t, period.

It is important that the line be tested using a procedure that is part of the“ tank and tubing test” and www. fueloilnews. com | FUEL OIL NEWS | SEPTEMBER 2025 31