Oil Boiler Not Working? Try These Checks Before Calling an Engineer
No Heating? Don't Panic Just Yet
There are few things worse than waking up to a freezing house on a winter morning. But before you frantically search for emergency heating engineers (and their hefty call-out fees), take a few minutes to perform these simple checks.
Many "boiler breakdowns" are actually simple issues that you can fix yourself in seconds.
1. The Obvious One: Do You Have Oil?
It sounds patronising, but running out of oil is one of the most common reasons for heating failure.
- Check your tank gauge: If it's showing red or empty, you've likely run dry.
- Don't trust the gauge? If you have a dipstick or a sight tube, double-check manually. Gauges can get stuck.
- The Solution: If you are empty, you'll need an emergency delivery. Warning: running dry can pull sludge into your fuel lines. You might need an engineer to bleed the system and clean the filters once you've refuelled.
2. The "Lockout" and Reset Button
If your boiler detects a fault (like a flame failure), it will go into "lockout" mode to be safe. You'll usually see a red light on the boiler's control panel or burner.
- How to fix: Press the lockout/reset button ONCE.
- Did it fire up? Great! It might have just been a temporary glitch (e.g., strong wind blowing down the flue).
- Did it lock out again? You can try pressing it one more time.
- IMPORTANT: Do not keep pressing the button. If it fails twice, there is a real fault. Repeatedly resetting it can pump unburnt fuel into the combustion chamber, which is dangerous and can cause a "bang" when it finally ignites.
3. Check the Power Supply
Is the boiler getting electricity?
- Fuse: Check your fuse box (consumer unit) to see if a switch has tripped.
- Switches: Has someone accidentally knocked the fused spur switch near the boiler? (Often happens when cleaning).
- Timer/Programmer: Is the display on? If it's battery-operated, do the batteries need replacing?
4. Thermostat Issues
Sometimes the boiler is fine, but the thermostat is telling it to stay off.
- Crank it up: Turn your room thermostat up to max. Does the boiler fire? If so, your heating is working, you just had the temperature set too low.
- Batteries: If you have a wireless thermostat, check the batteries. A "low battery" signal often stops it from sending the "on" signal to the boiler.
5. System Pressure (Sealed Systems)
If you have a "combi" boiler or a sealed system (no tank in the loft), check the pressure gauge on the front of the boiler.
- The Zone: The needle should usually be between 1.0 and 1.5 bar (often the green zone).
- Too Low? If it's below 0.5 bar, the boiler may have cut out to protect itself. You'll need to use the "filling loop" (a small flexible silver hose underneath) to add water until the pressure rises back to 1.0 bar.
When to Call a Pro
If you've checked all the above—you have oil, power, pressure, and the thermostat is calling for heat—but the reset button keeps tripping, it's time to call an OFTEC technician.
Common technical faults include:
- Clogged nozzle (needs replacing)
- Failed photocell (the sensor that "sees" the flame)
- Failed oil pump
- Motor failure
Pro Tip: When you call the engineer, tell them exactly what you've checked. "I have plenty of oil and I've tried the reset button twice" is very helpful information that saves them time.
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