OFTEC Cheat Sheet 2026

The 30 highest-yield OFTEC facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What should be done with the old oil filter element during a service? → Dispose of it as oil-contaminated hazardous waste through a licensed waste carrier
2. What is the minimum distance a plastic oil storage tank must be sited from a building under the Oil Storage Regulations? → 1.8 metres from a building (unless fire-protected)
3. What happens if the nozzle in a pressure jet burner becomes partially blocked? → Poor atomisation leading to incomplete combustion and sooting
4. What is the primary function of the photocell in a pressure jet oil burner? → To detect the presence of a flame
5. In a vaporising burner, how is the oil prepared for combustion? → By heating it on a hot surface until it turns to vapour
6. What is the difference between a single-stage and a two-stage oil burner? → A two-stage burner can operate at two different firing rates for better efficiency
7. What additional test should be performed if there is any suspicion of combustion gas spillage into the room? → A spillage test using smoke pellets or matches at the draught diverter
8. What are 'controlled waters' in the context of oil pollution regulations? → Rivers, streams, lakes, groundwater, coastal waters, and any watercourse
9. What is the danger of running an oil burner with a cracked combustion chamber? → Combustion gases including carbon monoxide can escape into the living space
10. In a two-pipe oil supply system, what is the purpose of the return pipe? → To carry unused oil back to the tank, aiding in de-aeration
11. When should a Bacharach smoke test be carried out during a service? → After the burner has been running for at least 5 minutes at stable conditions
12. What does the term 'delayed ignition' mean in relation to oil burners? → Oil is being delivered but fails to ignite immediately, causing a build-up
13. What is the fire separation distance for a steel oil storage tank from a non-fire-rated building? → 1.0 metre minimum
14. What is the required clearance between a single-wall oil flue pipe and combustible materials? → A minimum of 50mm clearance must be maintained
15. What happens if a conventional oil flue does not have adequate ventilation air supply to the room? → The burner starves for air, causing incomplete combustion and potential CO production
16. What is the maximum acceptable smoke number on the Bacharach scale for a kerosene-fired appliance? → 0 (zero)
17. How does the UK's net zero carbon target affect the oil heating industry? → It drives the transition toward renewable liquid fuels and hybrid heating systems
18. What is a twin-wall insulated flue system and when is it typically used? → A double-walled flue with insulation between the walls, used for external or exposed runs
19. In what order should combustion adjustments be made on an oil burner? → First check and set pump pressure, then adjust air settings while monitoring CO2 and smoke
20. How is the efficiency of a condensing oil boiler measured differently from a conventional boiler? → It must account for latent heat recovery from condensing water vapour in the flue gases
21. Which type of oil burner atomises fuel by forcing it through a nozzle under high pressure? → Pressure jet burner
22. What role does the Environment Agency play in investigating oil heating pollution incidents? → They investigate, enforce clean-up, and can prosecute the responsible party
23. What additional protection is required for oil tanks located near a boundary where there is a risk of vehicle impact? → Bollards or physical barriers to prevent vehicle collision damage
24. What is the correct electrode gap setting typically specified for a domestic oil burner? → 3-4mm between electrode tips
25. How should old oil filters and oil-contaminated materials be disposed of? → As hazardous waste through a licensed waste carrier with proper documentation
26. What is the theoretical maximum CO2 reading for the complete combustion of kerosene? → 15.2%
27. How often should a flue gas analyser be calibrated? → At least annually, with fresh air zeroing before each use
28. What is the purpose of a secondary containment (bund) for an oil storage tank? → To contain oil leaks and spills, preventing environmental contamination
29. Which British Standard governs the installation of domestic oil-fired heating equipment in the UK? → BS 5410 Part 1
30. What is the purpose of the flue spigot on the boiler? → It is the connection point where the flue pipe attaches to the appliance outlet