Expect the contractor to ask what fuel you burn, who supplies your electricity, and whether the trouble began with an outage. On site they typically check power and controls, the burner or ignition, the flue and venting, and any fault codes before swapping parts.
Lakeville's minimum lot size for a home with septic and well is 30,000 square feet, so basement doors, oil fill pipes, and outdoor heat pump units can sit well back from the road. After a storm, a shoveled path to the equipment and cleared exhaust and intake vents on the side of the house save time and help rule out a blocked vent.
If the fix becomes a replacement, permits come into play: the Building Department handles mechanical, gas, and electrical permits through Viewpoint, and the Fire Department issues oil burner permits. A temporary repair to restore heat may come first, with the permitted work scheduled afterward.