Check When It Was Last Serviced
Find your last CD/10 or service sticker. If it is more than 12 months old, you are out of warranty cover with most manufacturers — Grant, Worcester Bosch, Firebird, Warmflow and Trianco all expect annual servicing by an OFTEC engineer.
Look at the Flue Terminal
Step outside and look at where the flue exits the building. Heavy soot deposits, oily streaking down the wall or the smell of unburnt oil all point to bad combustion that an annual service should have prevented.
Listen for Lockouts
If the burner ignites with a heavy bang, fires unevenly or keeps locking out (red reset light), the nozzle is probably worn, the oil filter is blocked, or air has crept onto the supply line. None of these are jobs for the householder.
Check Your Oil Tank's Age
Modern integrally bunded plastic tanks last 15 to 25 years. Single-skin steel tanks last 10 to 15 and split without warning. If you do not know your tank's age, or if it is single-skin, book a tank inspection alongside the boiler service.
Look for Staining or Cracks Around the Tank
Walk around the tank in good light. Wet patches, hairline cracks, distortion in the plastic, daylight visible through a steel skin or oily soil under the outlet valve are all reasons to ring us today, not next month.
Measure to the Building
BS 5410 sets minimum fire-separation distances: 1.8m to a building wall with no windows or doors below tank height, 760mm to non-fire-rated boundaries. Tanks installed before the standard tightened may need re-siting or fire protection.
Track Your Fuel Use
If your annual kerosene use has crept up by 10–15% with no extra rooms heated, the burner is running out of tune or the appliance is sooting up internally. A service plus a clean usually claws back most of the loss.
Read Your Insurance Wording
Many home insurers ask whether the oil installation has been serviced annually and whether the tank meets BS 5410. A "no" answer can reduce or refuse a claim after a leak, fire or carbon monoxide event. Keep your CD/10 to hand at renewal.
Still Not Sure?
Book a professional OFTEC service and get certainty. You will receive a written CD/10 covering the boiler, the flue, the tank and the supply line.
Book Your Service