Oil boilers can run for a very long time when they are looked after. Many reach 15 to 20 years, and some go beyond. But there comes a point where keeping an old one going costs more than it is worth. These are the signs to watch for.
Your oil use is climbing
If you are using more oil to keep the house at the same temperature, and nothing else has changed, the boiler is probably losing efficiency. Older oil boilers can be well short of the efficiency of a modern condensing model, so a lot of the fuel you pay for is leaving up the flue instead of heating the house.
Track your deliveries over a few winters. Compare like with like, since a colder year uses more oil whatever the boiler does.
Soot, smoke or smells
A properly tuned oil burner burns cleanly. Soot around the boiler or flue, black smoke from the chimney or a strong smell of oil means incomplete combustion. Sometimes a service and a burner clean fixes it. If it keeps coming back, something is worn or failing.
Repeated lockouts and noisy running
A burner that locks out regularly, struggles to light, puffs when it starts or runs loudly is telling you something. It can be a blocked nozzle or a failing component, but when the faults pile up, parts and labour add up quickly.
Leaks
Any oil leak needs attention at once, whether it is from the boiler, the pipework or the tank. Oil can damage the property and the ground around it, and spills carry legal responsibilities. Switch the heating off and call an engineer.
Age and parts
Once an oil boiler is past 15 or so, check whether parts are still easy to get. If your engineer says the model is obsolete, or a major part is failing, replacement is usually the sensible route.
Uneven or weak heating
Radiators that are slow to heat, or hot water that runs out, are not always the boiler. Sludge in the system, a failing pump or a control fault can cause the same symptoms. Ask your engineer to find the cause before deciding. A power flush or a new part sometimes buys years.
How to decide
- Have the boiler serviced by an OFTEC registered engineer and ask for an honest opinion on its condition.
- Ask what the repair would cost and what that boiler's remaining life is likely to be.
- Get a quote for a replacement, so you can compare the two properly.
A new oil boiler comes with a guarantee and lower fuel use. If you are weighing it up, read our guide on whether oil is still the right choice, then get in touch. We install and service oil boilers, and our boiler installation page shows how we handle a replacement.
