Waste oil boiler flame head build

Topic: Waste oil boiler flame head build (Read 26 times) previous topic - next topic

Waste oil boiler flame head build

August 14, 2026, 08:57:53 AM

Now that a test rig was built and ran as predicted Now it is time to make the full on unit!

The air mixing plate I welded shims on and trimmed at an angle to hope fulling give the side discharge air some swirl to it and this all so centered the head.

I have to weld on yet a custom electrode support that is lower profile and more range of adjustment

The Nozzle assembly is made much heavier this needs to be insulated yet and a small cartridge heater may be added.

this is just the blast tube, next will be the mounting flange, then blower.

Oil and air feed will be taken of the rear of the blast tube assmbly

Re: Waste oil boiler flame head build

Reply #1 – August 14, 2026, 09:01:50 AM

the blast tube ruff out

Once done I will test fire the factory head and try and adjust mine to be as same as possible

Re: Waste oil boiler flame head build

Reply #2 – August 16, 2026, 08:23:12 AM

Well figured out how I will mount the assembly and stared

Ruffing out, think it is looking good.

Seems this is the way to go but how to mount it hard style?

Metal bracket steel rivets, yup I am liking this! Oil tube hooked up.

Now what remains? Combustion air adjuster, this will be very simple to make, just 2 disks with slots cut so they can be finely opened and closed.

The harder thing is the lid for the pot, and then the final compressed air hook up.
Once I figure out how to seal the oil pot up I can insulate it all. as the whole thing needs to hold at 80C apxly as this is the ideal temp for the oil mix I will be burning, if it where straight motor oil I could use a 70c set point

The electronics will be the easier thing, I need to do some test fires and carefully time how long it takes to draw up the oil and establish the flame to program the various delays and safeties into the controller.

The oil supply ended up longer than I'd have liked and I may need to add cartridge heaters to the nozzle assembly. This needs to work reliably at -40c, at current temps the oil will be warm enough, but once cold air starts blowing through the blast tube!!!! and the oil flow is tiny, ideally the combustion heat will keep it going but don't think I can count on it, but then again the combustion air will be from the same room as the boiler so this may just be a cold start issue.

So a few concerns and possible bugs I'll come across yet but this is going well so far. For the cartridge heaters thanks to 3d printing 25w 24v tiny units are widely available, I can run these from the zone control transformer

Re: Waste oil boiler flame head build

Reply #3 – August 17, 2026, 05:19:57 AM

Well got the last few things done, I decided to dismantle and insulate the oil line in the nozzle no pictures of that but just wrapped some fiber glass insulation then used masking tape to make a cover, it tends to hold up well in that application, but should I ever have to take it apart it is a consumable now.

Air adjuster made out of metal from a scrounged shelf, it was perfect gauge and had a nice pattern on it, sloppy cuts I know but function is the name of the game for this.

the oil feed line insulated

Air inlet and proofing switch.

At this point is just the electrical box, getting the wires all hooked up, safeties figured out how to route them as there is 2 independent systems, the oil heater system, that has its on safeties and proofs, then the gun system that will have it's own proofs and safeties. And both need to interact with the controller

the gun assembly needs to be inhibited till the oil is at its operating temp, then I want to lock out air pressure till the blower fan is proven, this will need to be done out side of the controllers logic. This is to ensure we're not spraying oil into the boiler with no combustion air, or spraying oil that can not be ignited. The air proofing switch is a compressor failure monitor, should compressed air fail, it will keep the oil solenoid locked out since no oil being used no reason to allow oil to the pot, it is a fail safe

Over temp, high / low oil level needs to be inside the controllers logic to sound alarm and lock out as fault

Re: Waste oil boiler flame head build

Reply #4 – August 17, 2026, 08:33:17 PM

Well finally got to the point of a basic functional test, 2h of rechecking adjusting, to figure out the only thing left was the nozzle its self, a .5mm, so removed it, put in a 0.8mm and bang, first cycle caught perfectly.

So need to see if I can salvage the nozzle as this whole system as designed around a .5mm nozzle, other than that every thing worked as intended. so need to do another cold dead start now the nozzle isn't a curve ball.

Re: Waste oil boiler flame head build

Reply #5 – August 20, 2026, 08:48:26 PM

Getting the electronics wired up

System powers up, oil pre-heater starts, upon reaching 80c switch closed with then closes the limit lock out loop enabling the controller

Call for heat comes in:

Blower motor and compressor come on at same time, this is during the pre purge and allows pressure to build in the line. Blower running closes the draft proving switch enabling air solenoid.

Fuel valve called to open, this opens air solenoid allowing pressure to the nozzle, and triggers the air proofing switch.

Air proofing switch on detecting set pressure then allows current to flow to the oil solenoid allowing oil to flow to the oil heater.

things to do is fabricate a nozzle intake screen, fabricate a cover for oil pre heater, and mount the burner mounting flange, install oil pre heater switch

this way should compressor fail there is no oil allowed to flow as a fail save.

Re: Waste oil boiler flame head build

Reply #6 – Today at 01:03:24 PM

Intake screen fabricated

Nozzle may plug once or twice on next batch of testing as any larger fillings may shed off despite best effort to clean but after that no more of that, ideally every thing should settle out long before hitting the screen in real world usage, but that added protection will make life easier down the road, as easier to drain the pot and hit it with a blast of cleaner and back up and running Vs dismantling the head assembly to remove the nozzle!