Thank you Whislenut, I should have elaborated more.
That boiler burns wood well, but it burns coal better. If you have a masonry chimney, I guarantee the chimney fire. It is a fine sectional boiler and has a pass through design that cools the exhaust and REALLY makes creosote, about as good as the newer Biazi's. My old partner ruined his dual flue chimney and went the Selkirk metalbesto's for years before giving in and learning to burn coal. He is sold on coal now. Coal is so much better that he had added sections to his unit to burn wood, it made it longer. This last summer, he took sections OUT because the coal puts out so much heat. A coal bed needs to be deep not long. Consider coal, if not, you have to be aware of this problem of creosote with that boiler.
He hooked his up the simplest way, that is his return water comes to the Chappee, and goes on thru the oil boiler. He turns the high limit down on the oil boiler to prevent firing and maybe even had a switch to shut the burner off. Remember, if you burn wood you have to have a dump zone. because wood will overheat and you need to consider the expansion tank although you are not adding a lot of water, the Chappee does not hold much depending which one you got. He has manuals on this unit if you need more info.
I recommend at least talking with him as he has 30 years of experience with that unit.