Oil-fired commercial boilers: what the annual service covers

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An oil-fired commercial boiler needs a service at least once a year by a competent oil heating engineer, covering the burner, the fuel supply and fire valve, the boiler and flue, and a check of the oil storage. Burner manufacturer Riello says in its commercial light oil burner instructions that "The combustion system should be checked at least once a year by a representative of the manufacturer or another specialised technician", and the Department for Education's estate guidance for schools says "Oil burners should be serviced at least annually, ideally at the end of the winter by a competent person." This guide explains what the annual service covers, what the rules on oil storage ask of businesses, and what site teams can safely check between visits.

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Commercial heating tips and advice · 2 November 2026 · Fast Commercial Boiler Help, Gas Safe 985448

Why oil-fired plant needs its own service

Many commercial oil boilers use a pressure-jet burner, in which a pump delivers oil to a nozzle and a fan supplies the combustion air. Riello's instructions say that "The periodic maintenance is essential for the good operation, safety, yield and duration of the burner. It allows you to reduce consumption and polluting emissions and to keep the product in a reliable state over time." They add that maintenance and burner calibration "must only be carried out by qualified, authorised personnel".

The UK code of practice for this plant is BS 5410-2:2018, Code of practice for liquid fuel firing. Non-domestic installations. BSI's summary says it "gives recommendations and guidance on the design, installation, commissioning and maintenance of liquid fuel firing installations for heating, hot water and steam supply services in non-domestic buildings", and that it also covers the selection and installation of the storage tanks that go with them.

Oil firing is a separate skill from gas. The Oil Firing Technical Association's course for servicing and commissioning two and three stage pressure-jet burners covers health and safety, "Safe electrical isolation", the selection, location and installation of fire valves, inspecting the oil storage and supply, and servicing and commissioning commercial pressure-jet appliances. Our engineers who work on oil plant are OFTEC trained. Where a site also has gas appliances, that gas work is for a Gas Safe registered engineer only.

What an oil-fired commercial boiler service covers

The exact tasks come from the boiler and burner manufacturers' instructions. As an example, the maintenance section of Riello's RL 42 BLU two-stage light oil burner manual lists these checks:

Oil pump. "The pressure must be stable and at the same level as measured during the previous check", and "Unusual noise must not be evident during pump operation." That is one reason last year's service report matters: the engineer compares readings against it.
Filters. The filters on the oil line, in the pump and at the nozzle are checked, and the engineer will "clean or replace as required."
Nozzle. "Do not clean the nozzle openings; do not even open them." The manual says "It is advisable to replace nozzles every year during regular maintenance operations", using nozzles from the manufacturer's list.
Fan and combustion head. Dust on the fan "will cause a reduction in the air flow rate and provoke polluting combustion", and the combustion head is checked for condition, position, dirt and heat damage.
Flame sensor, inspection window and flexible oil hoses. The flame sensor is removed and checked, the window is cleaned, and the hoses are checked to make sure they are "not crushed or otherwise deformed."
Boiler and flue. The boiler is cleaned to its own instructions "in order to maintain all the original combustion characteristics intact, especially the flue gas temperature and combustion chamber pressure". The manual ends: "Lastly, check the condition of the flue gas stack."
Fuel tank. "Approximately every 5 years, or whenever necessary", water and other impurities at the bottom of the tank are removed with a separate pump. This is a job for the engineer or a tank specialist, not site staff.

Your engineer will then check the burner settings and combustion, and record the results. For the wider picture of a service visit and the report you should expect, see what a commercial boiler service includes. Our oil-fired commercial heating page explains how we support oil boilers, and commercial boiler servicing covers booking an annual service.

The fire valve: a small part with a big job

A fire valve sits on the oil supply line and shuts the oil off if there is a fire or overheating at the boiler. Fire valve maker Fuelstop describes its valve as "designed to shut down the flow of fuel to the appliance in the event of the burner overheating or a fire near the appliance", with the valve installed "in the oil line at point of entry to the building" and its sensor "positioned above the burner in accordance with the burner manufacturer's instructions." The same sheet says "Fire Valves should be tested annually when the burner is serviced", and that the valve "cannot be reset until the temperature has returned to normal."

For site teams, the practical points are simple. Don't move, unclip or tie back the sensor or its capillary, don't store anything that could damage the oil line, and if the oil supply has shut off and you don't know why, treat it as a fault: leave the burner off and call an engineer rather than resetting the valve and trying again.

Oil storage: what the rules ask of businesses

In England, the Control of Pollution (Oil Storage) (England) Regulations 2001 apply. The Environment Agency and Defra guidance Oil storage regulations for businesses says you must follow the rules "if you've got an oil storage container with a capacity of 201 litres or more" at a business, or at a "public sector building like a school, hospital or leisure centre". Kerosene and diesel are both on its list of oils, and it warns: "You could be fined or prosecuted if you do not follow the requirements in this guide." Some key points from that guidance:

Bunding. "Fixed tanks must be bunded – you cannot use a drip tray for them", and a bund "must hold 110% of the capacity of the container." The guidance says double-skinned or twin-walled tanks do not count as secondary containment on their own.
Position and impact. Containers, fill pipes and draw-off pipes should be sited to minimise the risk of impact damage, "for example away from driveways, tanker turning circles and fork lift truck routes", or protected with barriers or bollards.
Taps, valves and gauges. Taps and valves that oil can leave the tank through must be kept within the bund and locked shut when not in use, and sight gauges must have "a valve that closes automatically when the gauge is not in use".
Overfill prevention. If the tank and its vent pipe can't be seen from where the tank is filled, "you must fit an automatic overfill prevention device to the tank."
Underground pipework. Without a permanent leak detection device, the guidance says underground pipework must be tested for leaks when installed and then "every 5 years if it contains mechanical joints" or "every 10 years if it does not".

The school estate guidance adds a sensible routine for any site: "All tanks, bunds and pipework should be regularly checked for signs of damage. It's recommended they are checked at least weekly, with a more detailed annual inspection and service by qualified inspectors to ensure that any potential defects are found and rectified." Other UK nations have their own rules, so check the guidance for where your site is.

What site teams can check between services

These are look-and-report checks. They do not involve opening the burner, changing filters, bleeding the oil line or resetting safety devices.

Check	What to report
Walk round the oil tank, bund and visible pipework (weekly is the school guidance's recommendation)	Damage, staining, a strong oil smell, oil in the bund, cracked or weathered tank walls, missing locks on taps or valves
Tank surroundings	New obstructions, vehicles or forklift routes close to the tank, damaged bollards or barriers
Plant room or boiler house	Oil smell, soot, smoke or fumes, unusual burner noise, combustibles stored near the boiler, ventilation openings blocked (see plant room ventilation)
Boiler controls	Lockouts: note the time and any fault light, follow only the user instructions, and don't keep resetting. Our boiler lockout log sheet helps the engineer diagnose faster
Pressure gauges on the heating system	Readings outside the range your engineer has set (see our pressure gauge guide)

Pressure systems and duty holder records

Many heating systems run below the PSSR thresholds, but some oil-fired plant produces steam or high temperature hot water, and HSE's INDG178 lists "pressurised hot water above 110 °C" among the relevant fluids that bring a system under the Pressure Systems Safety Regulations 2000. Where PSSR applies, the duty holder needs a written scheme of examination drawn up or certified by a competent person, and examinations under it are separate from the annual burner service. Our guide to written schemes of examination for heating plant explains when this applies.

Keep each service report, any tank inspection notes and any examination reports together. Insurers, landlords and auditors often ask for them; see heating maintenance records insurers ask for. If you want the annual oil service built into a wider schedule, BESA's SFG20 is "the industry standard for building maintenance specification", and CIBSE Guide M (Maintenance engineering and management) helps building operators "become more aware of their responsibilities and duties". Our planned preventive maintenance page explains how we schedule visits.

Oil boiler due a service, or showing a fault?

If an oil-fired boiler is locking out, smoking or smelling of oil, leave it off and call us on 0800 0996 007. Our OFTEC trained engineers look after commercial oil burners, boilers and their fuel supplies, and Gas Safe registered engineers (985448) cover gas and LPG plant on the same sites. See oil-fired commercial heating, plant room repair and emergency commercial boiler help.

Safety note

Under the Gas Safety (Installation and Use) Regulations 1998, gas work must be carried out by a Gas Safe registered engineer, and we apply that rule on every site. Don't attempt DIY work on gas appliances, burners, flues or safety devices. On pressure systems, trained site staff should stick to visual and gauge checks, log the readings and report anything abnormal. Never adjust, cap, plug or test-lift a relief valve yourself.

Talk to a Gas Safe commercial engineer

Fast Commercial Boiler Help is a Gas Safe registered (985448) commercial heating business based at 4 Market Hill, Clare, Sudbury, Suffolk CO10 8NN. Our team of over 10 local engineers covers East Anglia and East London, working on commercial boilers, plant rooms, water heaters, and warm air, radiant and unit heaters. We work on commercial premises only.

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Frequently asked questions

How often should an oil-fired commercial boiler be serviced?

At least once a year. Riello's commercial oil burner instructions say the combustion system should be checked at least once a year by a representative of the manufacturer or another specialised technician, and the Department for Education's school estate guidance says oil burners should be serviced at least annually, ideally at the end of the winter, by a competent person. Always follow your boiler and burner manufacturers' instructions, which may ask for more.

Who can service a commercial oil boiler?

A competent engineer trained in oil firing. Burner manufacturers say maintenance and calibration must only be carried out by qualified, authorised personnel. Oil work is separate from gas, so a Gas Safe registration on its own does not show oil competence. Our engineers who work on oil plant are OFTEC trained.

Does the fire valve need checking at the service?

Yes. Fire valve maker Fuelstop says fire valves should be tested annually when the burner is serviced. The fire valve shuts off the oil supply if the burner overheats or there is a fire near the appliance, so site staff should never move its sensor or capillary, and a tripped valve should be investigated by an engineer.

Do the oil storage rules apply to our business?

In England, the GOV.UK guidance says you must follow the oil storage rules if you have an oil storage container of 201 litres or more at a business or a public sector building such as a school, hospital or leisure centre. Fixed tanks must be bunded, and a bund must hold 110% of the container's capacity. Other UK nations have their own rules.

Does an oil-fired boiler need a PSSR written scheme of examination?

Only if the system is covered by the Pressure Systems Safety Regulations 2000. HSE's INDG178 lists steam and pressurised hot water above 110 °C among the relevant fluids. Heating that stays below those thresholds is generally not covered. Where PSSR does apply, the duty holder needs a written scheme drawn up or certified by a competent person.

Sources and further reading