I'm on my second year free heat from waste veggie oil, purchased this Colombia hot water boiler 4 years ago and finally got it wired and plumbed in just before X-mass last year. I became barren Realms apprentice during the installation he coached my over the telephone on how to wire up the aqua-stats, thanks Barren.
The furnace has been flaming out for the past week or so, I could always relight it by tossing in a piece of news paper but you could never count on it to fire on its own. So I decided to bite the bullet and source out the problem.
What I found is that the electrodes were totally encapsulated in carbon, after removing three nuts, air and oil line along with a quick disconnect multi wire power cord the burner is easy to remove. About 20 minutes work from removing to re-installing.
When I switched the power back on she fired up on her own.
You can actually but a kit to convert the standard type furnace oil burner to use waste oil, the kit is available here.
ckBurners - info & parts for WVO/WMO burners; reduce foreign oil dependence and carbon footprint
I have been saving all the oil burners that I come across, I'm going to convert one to use on the home foundry.
http://i1207.photobucket.com/albums/...rum/carbon.jpg
https://www.youtube.com/watch?v=mbyyUI6iv9Q