Before the burner gets a look, the supply side gets checked: tank gauge level, filter age and condition, fuel lines for air leaks and kinks, and the tank itself for weeping seams or a failing gauge. On the township edges, delivery timing is part of the system — will-call customers who stretch a fill through a cold snap become no-heat calls, and automatic delivery customers should still glance at the gauge monthly.
The one hard rule of oil triage: press the burner reset once. If it fires and holds, you bought time — but still book the visit, because the cause is still in there. If it locks out again, stop. Repeated resets flood the combustion chamber with unburned oil, turning a nozzle job into a dangerous puff-back cleanup.