How often
OFTEC, the trade body for oil heating, says appliances should be serviced at least once a year or as the manufacturer recommends. It also advises that any hidden or inaccessible oil pipework between the tank and the burner is pressure tested at least every five years. Use a technician registered with OFTEC: you can check the register on OFTEC's website, and a registered technician carries an ID card showing the work they are qualified for.
Booking away from the first cold spell, in late spring or summer for example, can make it easier to get a slot, and any fault is found before you depend on the heating.
What a service includes
OFTEC lists what a full service should cover:
- inspecting and cleaning the boiler and burner
- replacing consumable parts as needed, such as the fuel nozzle and flexible fuel lines
- checking the air openings the boiler needs to burn safely
- a visual check of the oil tank, pipework and filters
- testing the fuel for water
You should get a written service report afterwards (OFTEC's form is the CD/11). Keep it for your records: it lists the work done, the combustion test results and any parts replaced.
Why it matters
A boiler that is not burning cleanly can waste oil, build up soot and lock out when you need it most. The bigger reason is carbon monoxide, a poisonous gas you cannot see or smell. Building regulations guidance is clear that a carbon monoxide alarm is not a substitute for correct installation and regular servicing: you need both. The yearly visit is also when a leaking tank, a weeping filter or water in the fuel gets spotted early.
Carbon monoxide alarm rules by nation
| Nation | When a CO alarm is needed |
|---|---|
| England | When a new or replacement fixed oil-burning appliance is fitted in a home: an alarm in the same room (Approved Document J, from 1 October 2022) |
| Wales | When a new or replacement fixed, flued appliance of any fuel is fitted: an alarm in every space with a fixed combustion appliance, plus bedrooms and main living rooms a flue passes through (Welsh Approved Document J, from 6 January 2025) |
| Scotland | Every home needs a CO detector in any room used for living in that has a carbon-fuelled appliance, such as an oil boiler, or a flue; garages, cellars and attics are not included (Tolerable Standard) |
| Northern Ireland | When a new or replacement appliance not used only for cooking is fitted: an alarm in the same room, or just outside a boiler room or cupboard (Technical Booklet L) |
Alarms should meet BS EN 50291 and run on a battery that lasts the alarm's working life, or be hard-wired to the mains. The guidance puts them on the ceiling at least 300 mm from a wall, or high on a wall but not within 150 mm of the ceiling, between 1 m and 3 m from the boiler. Landlords also have their own legal alarm duties for rented homes in every nation.
If the alarm sounds
Turn the boiler off, open doors and windows, get everyone out into fresh air and get medical advice if anyone feels unwell. Do not use the boiler again until an OFTEC-registered technician has checked it, and do not try to repair it yourself. A service visit is also a good moment to check your tank level and compare prices for your postcode.
Common questions
Does an oil boiler service include the tank?
It should. OFTEC says the tank should be inspected every year as part of the heating service, along with the pipework and filters, and the fuel tested for water.
How much does an oil boiler service cost?
Prices vary by area and by what the visit includes, so ask for a written quote that lists the checks and parts covered, such as the nozzle, filters and the tank inspection.
Can I service my own oil boiler?
It is not advised. OFTEC recommends a registered technician, who is trained and assessed to set the burner up safely and gives you a written service report.
Do I need a carbon monoxide alarm with an oil boiler?
Yes when a new or replacement boiler is fitted, in every UK nation, and in Scotland every home needs one in any lived-in room with an oil boiler or a flue. Even where it is not required, an alarm to BS EN 50291 is a sensible precaution.
Sources
- OFTEC: Your home guide to liquid fuel heating
- GOV.UK: Approved Document J, combustion appliances and fuel storage systems
- Welsh Government: Approved Document J, combustion appliances and fuel storage systems
- gov.scot: Satisfactory fire and carbon monoxide detection, tolerable standard guidance (chapter 17)
- Department of Finance NI: Technical Booklet L, combustion appliances and fuel storage systems
Prices on this page are Fueltool's live figures for 25 October 2026: the typical (median) listing for standard heating oil, before VAT unless it says otherwise. How they are worked out.
Today's price
Typical heating oil price today: 114.1p a litre before VAT, about £1,198 for 1,000 litres with VAT.
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