Oil furnace & boiler troubleshooting guides
Oil furnace and boiler troubleshooting guides, sorted by symptom. Not sure which one? Start with the oil furnace troubleshooting chart. Each guide starts with the quick answer, walks the checks that are safe without tools, and tells you exactly where homeowner territory ends and licensed-tech work begins.
No heat & won't start
- Furnace won't turn on Power, thermostat, and the first three things to check
- The reset button, press once Why once only, and what a lockout means
- Fires, then shuts off Short-cycling and cad-cell flame faults
- Blowing cold air Burner versus blower, and which is failing
- Ran out of oil What happens to the system, and how to restart
- Bleed the line after a run-out Clearing air from the fuel line, step by step
- The full decision chart The complete no-heat flow, start to finish
Smells & safety
Tank & fuel
- Water in the oil tank How it gets there, and what it does to the burner
- Read your tank gauge Float gauges and turning a reading into gallons
- What is Bioheat? Biodiesel blends in plain terms
- Bioheat vs heating oil What changes for your equipment
- Heating oil vs diesel vs kerosene When a substitute is safe, and when it is not
- B20 blend problems Filters, gel point, and older systems
- Oil heat vs gas An honest comparison, no marketing
Costs & replacement
How it works & reference
- How an oil furnace works The burn cycle from thermostat to heat exchanger
- Pump prime mode, by control Technician reference: entry, time limit and exit for each primary
- Energy Kinetics System 2000 Owner's guide: the E140 light, the one-reset rule, and faults
- Burner specs by brand Beckett, Carlin, Riello, Wayne burner specs and codes
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