Hi All, I've been on the board for a few months now gathering info. and just installed a used/refurbished EFM 520 about a month ago. I just couldn't justify buying any more oil @ $4.25+ gal! Anyway, overall I think it's running well, though lately now that it's been warm I've noticed that Im getting a lot of unburned coal in the ashes. By a lot, I think the ash pan is maybe 1/5-1/4 unburned coal. Since I didn't have a lot of time to play around with settings before it got warm, I've lowered the feed/air twice. I started on 5/4.5 but would always hit the high limit since I'm only heating about 1700sqft. Went to 4/4 and the stoker would run longer, maybe 20-30 minutes on a call for heat. It got warm out so I figured I'd try 3/3.25 which would make the stoker run a little longer on a call.
My other settings are: Hydrostat 3150 150 low / 200 high limit, Honeywell Timer- 2.5min every half hour
My main suspect is not enough draft, I get about .02 at idle and then when running it usually hovers around .03-.04 now that it's warm out. When it was cold when I first installed it would stay near .05. I've tried running 3 feed/3.5-3.75 air to see if it would help but it just seems that the stoker runs so infrequently that unburned coal sits on top of the ash ring and falls off the edge with it. The ashes seem clumpy /clinker but I don't think I should use any less air. I'll attach some photos of the fire at 4/4 and 3/3.25. I'll throw some in of the install too for your entertainment.
So what's a good strategy for running it in warm weather? More feed/air with shorter run times or slow and steady? I'm not going to use it for DHW this summer, but will probably add a coil eventually since electric has gone up considerably. I'm also thinking of adding a draft inducer since my chimney is an exterior masonry style and a little too short. Eventually I'll get around to making it taller but for now it's going to have to wait.
Any thoughts would be appreciated.