Well first I must apologize - because I re-read my post this morning and saw my chimney typo - its 55 feet with a 5 - not 75 with a 7. Sorry about that all big chimney fans. LOL
Nonetheless it's a decently large stack for a house. And I should also disclose that I am an eager but amateur home renovator and careful and methodical learner with a keen interest in technology and things mechanical - but I am not a professional at any of the trades. Sometimes I tackle projects that 90% of folks would say are too big for me - but at the same time I work very hard to read all relevant materials, follow code, and learn as much as I can so I don't blow myself up or burn the house down, and make generally sure that I can be proud to show my work to anyone. By day I write computer software for a living.
I also had help installing. A friend (who probably hates me now LOL) pitched in and helped me with the sheetrock, pulling wire, and assembling the framing for the coal bin. With his efforts and mine it was 500 hours elapsed time, but really closer to 900 or 1000 hours of total man hours to install everything. Finally, my sister's fiance helped assemble the manifolds and made sure that I didn't screw up in the piping plan in any big way for the mains, hot and cold water feeds, water heater, backup systems, etc. The electric I handled myself on the controls for the dual system.
The house is 1899 vintage - edwardian style - 6400 sq feet, stone, 3 stories, with 49 original double pane windows (some up to 65 wide by 84 high) with no storms and a glassed in solarium. Even so, The demand is probably small for the output of the S500. When I started this I was naive - and I started with the premise of matching the btu output of the oil burner already installed which was 450,000 - not realizing that the reason the big oil burner gave so little heat was because a previous installer had used a toy taco circulator to pull water through a 3/4" housing that connects to 24 radiators on 3 floors through 4" mains. The S500 really DOES loaf in my house. If I had to do this over again I might have considered pairing an 260 and a 130 and be able to reduce fire as my load fluctuates throughout the year - but ... what's done is done. I realize now that in the slack season I am probably dumping heat up the chimney a lot of the time - however by learning to program the grate down low, my coal usage during slack demand is very very low. I barely fill an ash pan a week in the shoulder seasons (spring / fall). The fire has never gone out even after not being fanned for 4 or 5 days at a stretch.
I am also planning for the future, and I have 2 unused taps on my manifolds - one is a 1 1/4" feed for the pool heater which is next year's project, and there is a 1 1/2" feed for my garage / carriage house - which is around 3000 sq feet on 2 floors and currently unfinished. My plan is to run PEX out to the garage in the future where I would like to minimally heat the car area, and add a living unit upstairs. With those loads in mind it seemed better to err on the side of at least matching the output of the oil burner. The house itself is all radiators - which had been converted from steam to hot water many years before I got the place. The mains are all 4" in the basement - so I have a very large mass to heat before the house gets toasty. At the same time, those big pipes being warm helps to keep the basement mildew free and toasty in the winter without any other dehumidifiers or effort.
I used to freeze in this house, and in 2007 paid nearly $10,000 in oil for the privilege. Now with the coal unit, the house gets all warm and toasty for the winter. It has become a pleasure to get up in the morning and enjoy the all over sensation of warmth at any corner of the house - not to mention hot water that never runs out!