Originally Answered: Oil furnace only turns on when I press reset button?
Oil furnaces are definately more hastle than gas or propane, because they are based on old school technology and rely mostly on mechanical adjustments, and are a lot more volatile.
The safety circuit on an oil furnace is designed to try lighting 3 times and then gives up and locks out after the 3rd try.
It could be that your oil nozzle is gummed up and need to be replaced. If you have a lazy flame your fire eye will not see it.
It could be your electrodes need a good cleaning or replacement.
The insulators of your electrodes could be cracked.
Your fire eye lense could be in need of cleaning, or need to be adjusted to better see the flame(on some units).The fire eye module or the primary control itself may be going bad.
The transformer contacts and buss bars may not be making good contact.
Could be a lack of pressure from your pump.
Could be the burner blower fan is full of crud and not pushing enough air into the firebox.
Air in the line, Dirty filter, crud in your tank, poor fuel quality, Somebody stepping on your supply line and kinking or partially flattening it.all could be factors.
There are just too many variables with oil furnaces to troubleshoot over the internet. And it can be dangerous if not handled properly.
Check the simple things first, make sure supply line is sound, are the fittings tight and not sucking air,replace filter,bleed lines .
If it actually relights with one reset you 're fine but if it doesn't PLEASE,please don't keep hitting the reset button, it if trips there is a problem that needs addressed.
I've had oil furnaces blow apart on me because the homeowner filled the firepot with too much oil by reseting it waaaay too many times before it lit.
Based on what you've written it doesn't sound like you have an ignition problem, but more of an issue with fuel supply, flame monitoring, or possibly componet failure.
Call the manufacturer and get the name of a recommended /reputable HVAC company in your area.
A lot of HVAC company's don't like to work on oil furnaces anymore because they are such a hastle. I'm being optomistic here but The service guy you had may just be inexperienced with oil burners.
But then again........you could just be getting jerked around.