Don’t be uptight: Knowing the proper way to install a nozzle can defuse nozzle-related problems


by George Lanthier

Recently, I’ve been hearing a lot about one of my favorite things to teach and one of my pet peeves. I did an article on this subject about 10 years ago, but it seems at every seminar I teach, it keeps coming up. What makes it even sadder is the cause and the fact that we only have ourselves to blame.

Originally this article featured my characters Bruce & Bubba and some excerpts from my book COMBUSTION & Oil Burning Equipment, so with those points made let’s get back to the continuing adventures of those fictitious and now infamous personalities.

By the way, many people still ask me if Bruce and Bubba exist. Well, of course they do, don’t you still believe in Santa Claus and the Easter Bunny? OK, how about the Boiler Fairy? You know, the one that cracks boilers in mysterious ways in the middle of the night? But, look at the bright side, the Boiler Fairy does bring you installations galore. The truth is that Bruce and Bubba are composite characters. They really don’t exist as individuals, but are made up from many people I have known over the last 38 years, including my past and current mentors and students. But remember, it also takes in a lot of people, including the good, the bad and the incredibly stupid, to make the world go round.

Bubba comes into the shop one morning and finds the new apprentice, Billy Bob, working on a problem at the workbench. Since most people think his name is too long, they call him B.B.
‘Good morning, B.B. What are you doing there? It must be important, because you’re not known for getting in this early?” asks Bubba.

‘Well, I’ll tell ya, Bubba, I had this terrible after-fire on a burner last night. It also had a cockeyed fire and so I checked everything and couldn’t seem to find anything wrong, but what an after-fire! On top of that, the boiler was in the weirdest shape. The combustion area was white on one side and black on the other. Hey, that crack about when I come in isn’t fair,” says B.B. ‘I was the only one on call last night, ya know!”

‘Sure, sure, sure,” answers Bubba. ‘We all get our turn, so what’s the problem?”
‘I may be crazy, but it looks like maybe there’s an air leak at the nozzle adapter. I had a spare drawer assembly on the truck, so I swapped it out. Ya know what else? That new assembly fixed it. That’s all, just swap the drawer assembly and away goes the problem. So, I’m trying to find the problem, but not having any luck,” says B.B.

‘Here, try this,” says Bubba. ‘Put some compressed air down the nozzle line. Then we’ll brush some soapy water on the nozzle and adapter to see if it bubbles.”

‘Wow, that’s cool? Where did you learn how do to that?” asks B.B.

‘My Uncle Bruce taught me that about nine years ago. Don’t forget it, this really comes in handy on finding gas leaks, leaks on air-conditioning systems or just about anything under pressure,” explains Bubba.

‘Yeah, but I never thought of trying that. Hey, look at those bubbles! Holy cow, now that’s a leak!” exclaims B-B.

‘Did you have any oil in the tube or chassis?” asks Bubba.

‘No, not really, just an after-fire and when the burner ran, the fire looked tilted to one side. I guess it was like those compression fittings, they can leak air, but not oil. OK, so let’s pull the nozzle out and take a look. Wow, look at this Bubba! Look at the burr on this nozzle adapter; ya think that’s it?” asks B.B.

‘Yup, I’ll bet you that’s it.” says Bubba. ‘It’s the old ‘how tight does a nozzle have to be?’ problem. Let’s resurface the adapter with this tool I have and try it again.”

The tool in question, Figure 1, is the ‘M-E-D #517 Nozzle Adaptor Re-Fracing Tool” and after using the refracer, the nozzle adapter will not only have its threads cleaned and refurbished, but it will also cut a new surface onto the adapter face.

Regretfully, the reason why you need to do this is simply because somebody ‘over-tightened” the nozzle in the adapter to begin with. Like many tools, this one is only needed because somebody screwed something up and this happens just too often from talking to the hundreds we put through seminars every year. I don’t really know who’s to blame for all of this over-tightening, but I do know that as an industry we just don’t seem to understand the meaning of the word torque and the person in question is named ‘the animal.” The reason I know that is because the comment always seems to be, ‘I’d like to get a hold of the animal that over-tightened this.”

The correct procedure for the installation and tightening of nozzles is something that seems to get passed over in the initial training of apprentices. Regretfully, that’s sad, because most bad habits stay with us for a lifetime. The only way a professional oilburner technician should install a nozzle is with a nozzle wrench. A nozzle wrench is shown in Figure 2.

This particular wrench is the Firedragon #123 and is also available from us and makes a great companion to the nozzle adapter tool. You can find both on our Web site at

Let’s begin by looking at some of what I have to say about nozzles in my book COMBUSTION & Oil Burning Equipment:

‘The nozzle is a highly engineered and machined product and it should be treated as such. The first step to treating a nozzle properly is to install it and not contaminate the strainer or orifice. That means not touching the nozzle except by the hex body.

‘Second, deliver clean oil to it. That means not only the oil coming from the pump, but when a nozzle is replaced, the nozzle adapter and the nozzle line should be cleaned and flushed before the new nozzle is installed.

‘Third, ensure that the nozzle adapter threads are not stripped and that the face surface of the nozzle adapter has no burrs or nicks. Stripped threads and uneven face surfaces can throw fires off-center and lead to problems, including soot-plugged heat exchangers. Tools are available for the repair of threads and surfaces, and for the proper tightening into the adapter.
‘Fourth, by use of any of the gauges supplied by manufacturers, verify nozzle concentricity. The proper gauge must be used for the specific burner in use, but this dimension verifies that the nozzle is positioned directly in the center of the head.

‘Finally, before the nozzle and the drawer assembly are put back into operation, a complete flushing of the pump and pump-connecting line into a suitable container is required to prevent contamination of the new nozzle.”

So, by holding the nozzle only by the hex body and not touching the strainer or orifice area with our hands, we bring the nozzle up to ‘finger-tight.” Then using a nozzle wrench, all you have to do is bring the handles together.


It seems in my article ‘Checking Low-Water Cutoffs” in May I made a couple of nasty assumptions and I apologize for that. It was really stupid on my part since my Second Rule of Service is ‘assume nothing” and so, with that out of the way, let me repair my ‘errors of omission.”

I assumed that everyone could figure out by the picture that we wanted one lead to go to the cutoff probe electrode and the other to boiler ground. Some probes have grounding/mounting plates and that will also work. We’re passing a small voltage charge through the probe and the boiler water and the idea is to see if the probe electrode is clean enough and that the probe is in fact properly grounded to do just that.

My second assumption was in regards to the readings from the meter. They should be obtained by placing your meter probes into the two test jacks and the readings should be around 9 volts, the output of the battery.
I appreciate your e-mails and comments and again my apologies for the assumptions.

The trick is where to put those handles to begin with. Let’s say that you haven’t bought a nozzle wrench yet. Where do you put the wrenches? First of all, I don’t care what you use on the nozzle adapter, but a 1/2-inch open end is what most pros use in place of a nozzle wrench. I do care and so do most nozzle OEMs and burner manufacturers what you use on the nozzle, and that should only be a 5/8-inch box wrench so that you place equal pressure on all of the hex surfaces of the nozzle. It’s about torque and pressure and being a professional, got it?

You put the 1/2-inch wrench so that the handle is at six o’clock and the 5/8-inch handle is at about 4:30 and tighten. That spacing turns into one-eighth of a turn, or 45 degrees apart. Set the handles and then pull them together and that’s all you need to reach torque. Keep in mind you are either mating brass to brass or steel to brass on what is supposed to be two perfectly even and flat surfaces. If you do this every time and show as many others as you can you won’t ever need the 36-inch and 48-inch pipe wrenches to take them apart again. Some day we all might not need the adapter tool, but I bet you could use one now.

Well, that’s my spin on what seems to be this age-old problem, and be honest, did you know all of this beforehand?

George Lanthier is the owner of Firedragon Enterprises, a teaching, publishing and consulting firm. He is a proctor and trainer for the industry’s certification programs and is the author of nine books on oilheating and HVAC subjects. He can be reached at 132 Lowell Street, Arlington, MA, 02474-2756. His phone is (781) 646-2584, fax at (781) 641-7099 or e-mail

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