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Heating engineer · Brussels and Wallonia
The oil burner locks out
When an oil burner can't light its flame, it locks out and a red light comes on. A few checks before resetting avoid making the problem worse.
The most common causes
Tank empty or nearly
The burner draws in air, or the sediment from the bottom of the tank.
Clogged oil filter
Especially right after a delivery: sediment at the bottom of the tank gets stirred up and blocks the filter.
Nozzle, electrodes or photocell
The nozzle sprays the oil, the electrodes light it, the photocell sees the flame. When dirty, the flame won't hold.
The cold
In a hard frost, oil can thicken in a pipe running outside or through an unheated room.
What you can check yourself
- Check the tank gauge: if there's little oil left, have it filled before resetting.
- Was there a delivery just before the fault? Tell us on the phone: it's an important clue.
- Check that the burner switch and the thermostat are actually calling for heat.
- Reset once with the red light's button and let the burner run its start-up cycle.
Don't
- Resetting more than twice in a row: unburnt oil can build up in the boiler. For a Riello burner, the manufacturer asks for no more than two resets.
- Taking the nozzle, electrodes or filter apart yourself.
- Smell of smoke or oil in the boiler room? Switch the burner off and air the room.
Call us if…
- The burner locks out again after a reset.
- It locks out often, even if it restarts.
- The fault comes right after an oil delivery.
- There's smoke, a smell of oil or soot.
What does a repair cost?
Call-out and diagnosis: €125 excl. VAT. The repair is extra, and you get its price before we start. We usually come within 24 hours (working days) and let you know 1 hour before we arrive.
This advice applies to most boilers. Every appliance has its quirks: if in doubt, your own manual applies, and we're happy to answer on the phone.
Frequently asked questions
My burner locks out after an oil delivery: why?
During delivery, sediment at the bottom of the tank gets stirred up and can block the filter. Don't keep resetting: call us, the filter usually needs cleaning or replacing.
How many times can you reset an oil burner?
Once, twice at most. If the red light comes back, the burner is reporting a real problem, and repeated resets can let oil build up in the boiler.
Find out more
A breakdown, a question? Get in touch.
Call us or message us on WhatsApp. Or leave your number, with a photo of the boiler if you like: we'll call you back.
