Register Now


Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

How to Replace The Nozzle and the electrodes of an Oil Fired Heater

4.6/5 - (18 votes)

OK, now before we start the most important thing to do here is turn the power off to the unit.

Oil feed disconnectedPin


Oil feed disconnected

Remove the two little tabs/screws that are holding down the transformer and flip it out of the way. At this point, you want to make sure the power is off. Those two little springs on the transformer are what give the electrodes the high voltage of power that is sure to wake you up.

The picture to the left shows the oil feed line disconnected with just some paper towels under it to pick up any oil that may come out. Remove the line and the nut on the oil feed pipe. That is the only thing holding the whole assembly in.


Now all you have to do is twist and pull the unit out. Just be gentle while doing so.

You’ll notice some wires, no biggie, remember the power is off, right?

OK, now that you got the unit out let’s take a good look at it. More than likely yours doesn’t look as bad as this one. This one went many years without being serviced. The dead center you’ll see the nozzle. For now, leave it alone while you clean the heck out of this unit. The funny shape you’re looking at here actually creates a twisted airflow to the flame that will also have a twist to it as well. Allowing the air to come in, and as you can see this one here was about 75% plugged up. So with a small wire brush and rag, you should clean this up real well.


An automotive carburetor cleaner works well on this.

Now here you see the electrodes. Now to the untrained eye, they look in good shape. However, they are supposed to have a point at the end. Notice all the unburned wet oil. Yup, not good.

Now remove the old electrodes held in by that one screw in the center with a bracket.


Removing the nozzle is as easy as can be. However, if done wrong you’ll be in for it. YOU MUST USE TWO WRENCHES AT THE SAME TIME. You must do this, otherwise, you can twist everything. Once you unscrew and remove the nozzle, keep it. Don’t get rid of it.


You’ll notice the old nozzle to the left in the picture. Clean the sides of it and you’ll see some numbers on it. One set will be the flow, this one is 1.00 Which means 1 gallon per hour. The 70 means the degree to it will spray (flame). Make sure you get the same one. For other reasons, yes you can change this to a different one. Say one that uses more oil per hour to make more heat. But that doesn’t always work like that. So check your system tags for the specs on which one it wants. Chances are yours could have the wrong one in already and that’s why you’re using so much oil.


Just tighten a little, too much and you can break the electrode.

OK, so did everything go so far, I hope. This is the part that separates the boys from the men. Why, simple, boys will read those instructions that came with the electrodes and tool you now see. Go ahead, this is the internet. No one will know you went to read them before you came back here to read more. From this point, if you did read those you won’t need me anymore


But just in case your dog eats them.

READ THE GAUGE. On the gauge/silver tool, there are marks. One marks the cl (centerline) of the nozzle. Hold the gauge as shown and line up the tips of the electrodes to the two outside lines of that centerline. It’s about the thickness of a nickel. However, you’ll need those instructions, in there you’ll see that they have different specs for different units. The one here wanted the trips 5/16 above the nozzle trip and 3/32 apart.


All together and double-checked, oh, and all nice and clean. Don’t forget to change the filter before you start it up.

All back in and waiting to make some heat. Just go slow, take your time, and be clean. Place the transformer back down, tighten the screws, change the filter, bleed out the air and you’re now a pro.



Comments ( 6 )

  1. this was exactly what i had been searching the 'net for! I'm very mechanically inclined but seeing what i had been looking for in pictures always helps before i make a bonehead mistake that will cost more than i wanted to spend. very helpful.

  2. Yeah I wish I had some pictures my self when I was doing this for the first time. Oh boy how I remember that day. Thanks again

  3. Amazing! Great walk through instructions and great pictures! It's a wonder professional heating companies don't put a "hit" out on your life for doing us DIYers such a favor! So many home owners are desperately trying to save a few dollars in this intimidating economy. Thanks, again!

  4. Thanks for the tips. Wasn’t exactly what I was looking for but helped fixed my issue atleast temporarily.
    Local shop wanted 150 to come out & quote repairs. I am like that cost 3x as much as it cost to have it repaired a few years ago.

    Thanks again. mine just needed contacts cleaned for now. But I am sure it needs a bit more cleaning.

Leave a reply