I take it this is for a large building. Has anyone done a heat loss calculation on the building to make sure your boiler is sized properly?

There are gas burners that basically replace the oil unit. They are called power gas burners, and operate on the same air tube principle. As long as your Smith boiler is certified to run with gas, it shouldn't be a problem at all. But if the boiler is oversized it becomes inefficient.

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1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma