It's been some time since I've updated, after this cold snap I figured the time was ripe!
Built myself a bigger bin (instead of the 55 gal drum). It works pretty well and can hold around 400 lbs if needed.
I also did a test trying the 'low and slow' method by doing a pulley swap and getting a speed reduction of 40% down to 1:1 fan speed to motor speed yielding 1725 RPM. I ran this for several weeks and found I would burn about 1.5 x (70 [IAT] - OAT average) lbs per day. So if the outdoor temperature was an average of 30 (say, a high of 35, low of 25) 70-30=40 x 1.5 = 60 lbs it was just about dead on. Usually adding up to 5 lbs, (this included domestic water)
I was very happy with this (burning buckwheat still)
After I had some issues I switched back to the original pulley setup and during these cold temps I was pretty close to that same value of 1.5 - so I don't think I gained much of anything.
Saturday morning I topped off my bin and put a new ashtub in: in 2.5 days (60 hours) I burned 260 lbs
some of the nights were in the singles and the days in the teens and MAYBE low 20's - sunday was 20 degrees for almost 24 hrs but a LOT of wind. I know I burnt 3 buckets in that spell.
I also weighed my ash tub
16 lbs! ! ! !
I don't think I've ever seen that kind of ash/coal ratio- it could be skewed a little because there might be a giant lump waiting to fall -but still 3-4 lbs increase is still VERY good. I go 2-3 days on a ROUND ash tub in these cold days, never did that with the keystoker, that's for sure. Best I got with that was 14% ash to coal ratio.
Currently my boiler control is 160-180, this insures a GOOD solid run everytime and never gets low enough where the domestic struggles. My runtimes are close to 15 minutes-I'm happy with that. this is not setup as a highlow, this is a setting of 170 with a 10 degree hysterisis.
I also have the timer setup to run 1 min/hr - but it runs off the NC terminal of the relay, so as long as there has been an actual 'heat call run' within an hr, the timer will never run. This is to keep the fire stimulated on warmish days but unlike a traditional timer it's running the 'off' cycle first (thank you Rob!) - it works like a champ -nothing more annoying than a timer cycle just after a heat call - wasted coal!