Diagnosis here begins before anyone drives anywhere. The phone triage asks fuel-specific questions — oil callers get burner-history and tank questions, gas callers get ignition and condensate questions — plus one Morrisville-specific question: was the home converted from oil to gas? Conversions hide assumptions: a gas boiler on a distribution designed for oil-fired temperatures, legacy oil equipment still in the basement, and controls set for the wrong fuel's habits.
The on-site visit then tests the suspected components first — igniter, flame sensor, electrodes, circulator — and separates boiler faults from distribution faults, which are common in rowhomes where zone valves and air cause the cold rooms. If you are unsure which service fits the symptom, the emergency page covers the no-heat-in-freezing-weather line, and the Morrisville guide maps the local fault patterns.