What if instead of making those complex constant leveling devices for siphon nozzles, you just used an air/liquid solenoid valve like the one the stock burner uses and wire it to the solenoid that allows air to travel through the nozzle. This way oil will flow when needed and will stop when the burner turns off. You can’t give me the excuse that it will drip out of the nozzle when the burners not on, because it will be exactly like a stock burner set up. I’ll try it soon and let you guys know. Keep it Simple.
While I appreciate creative ideas, I wouldn’t recommend a coffee mug heater because of the safety issue. It’s so easy to build an air/oil preheater anyway. I don’t use a constant leveling devices. I have two solenoids on my system, one which is on the fuel line just before the preheater and the same for the air. Because my source of veg oil is higher that my oil burner, I prefer this method.
Siphon only systems you need the oil at a constant level under the nozzle… u cant just run from the tank to the nozzle…when the tank is full with 270 gallons of oil and the tank outlet is even with the burner… you will have a couple pounds of oil pressure… and when the tank is almost empty it will almost require sucking the oil from the tank… this will change the flame a lot…even atmospheric pressure changes could possibly change the burn rate.
And you will still have nozzle drip problems with your idea because the oil will be expanding inside the heater.. and will be forced out the nozzle… unless you are lucky enough to find a ($150-$300) solenoid valve rated for use at over 300 degrees F with Zero Differential Pressure… then you can put that between the heater and the nozzle.