Oil Fired Boiler Service

A good oil-fired central heating system will contain the same controls as a modern gas-fired system. In particular it should have:

• a room thermostat, ideally located in a living room, not the hallway 

• thermostatic radiator valves (TRVs) on all but one of the radiators 

• an electronic 7 day timer with separately programmable hot water and room heating 

• a cylinder thermostat on the hot water tank 

• the boiler and thermostats wired in an interlock to prevent short-cycling when there is no demand for either hot water or room heating

Modern oil-fired boilers can be highly efficient and manufacturers claim net seasonal operating efficiencies of up to 97%. As with gas boilers, condensing boilers are likely to offer the greatest efficiency, and there are now over 90 “A” rated models on the market. From 1st April 2007 it became mandatory to install condensing oil boilers to comply with Building Regulations. You can check how a boiler rates by visiting the SEDBUK website, but it is worth noting that non-condensing boilers have their rating capped at 85.7% for the purposes of the SEDBUK database, even if test results have shown an efficiency above this. For more information you are recommended to speak to a reputable boiler manufacturer or installer.

Oil boilers are available with both balanced flues (where the air for combustion is drawn in through a pipe concentric with the extract flue) and with open flues, where the air for combustion is drawn from the room in which the boiler is sited. Although Building Regulations permit both types of boiler to be located in domestic garages, we recommend that only balanced flue boilers are used in those areas. Most modern boilers use a pressure jet burner; although some vaporising burner machines are still available on the market, they may only be fitted into a limited number of locations.

Almost all UK domestic central heating systems use 28sec oil, which is sometimes known as kerosene. This fuel burns more cleanly than heavier oil products such as gasoil, which is also known as 35sec heating oil. 28sec oil can also be used in kitchen ranges such as AGA cookers.

As the sulphur content of oil has fallen, some domestic oil suppliers have added additional lubricants to kerosene to enable fuel to be pumped to the boiler more easily. This is not usually necessary for most systems, as modern pumps have been engineered to operate effectively with low-sulphur fuels, but if you are unsure if you would benefit from using such fuels, speak to your equipment supplier.

HVO (Hydrogenated Vegetable Oil) is on it way!

A modern high-efficiency oil system can provide an environmentally acceptable alternative, especially for homes that are not connected to the gas main. As with all heating systems, regular servicing will help the boiler burn more cleanly and efficiently, and it is important to match all boilers to modern central heating controls.

Many people are concerned by the threat of Global Climate Change, and are keen to reduce their personal emissions of carbon dioxide (CO2), the main gas contributing to this effect. Official figures from the UK’s Department for the Environment, Farming and Rural Affairs (Defra) indicate a carbon content for domestic heating oil (kerosene) of 0.24kg CO2 per kWh, compared to figures of 0.214kg CO2 per kWh for LPG and 0.19kg CO2 per kWh for gas. However, these figures are for gross calorific values, and a typical “A” rated condensing oil boiler achieving 95% efficiency would be responsible for around 5% more CO2 in use. Equivalent gas condensing boilers are a little less efficient, reducing the carbon penalty for oil systems to less than 10% compared to LPG and around 20% for mains gas.

Although there is no legal requirement for oil boilers to be installed by a specially trained person, we strongly recommend that all servicing and installations are carried out by people registered with OFTEC, the Oil-Fired Technical Association, as the manufacturers will only validate guarantee when properly installed and commissioned by an OFTEC registered engineer.

You may also have to check whether or not your house insurance is current and up to date, if you do not use an OFTEC registered engineer.

We also recommend that all oil-fired systems are fitted with an automatic shut-off in the event of fire. This will prevent a fire spreading to the external oil tank. Most tanks are now made of plastic and so are easy to maintain; there are quite complex regulations on where they may be sited, your OFTEC registered engineer will be able to advise you on these matters, if you do not have one, you can contact your local Council’s Building Control Officer, who should be able to advise you on these. All boiler installations are required to conform to Part J of the Building Regulations, and oil-fired systems should also meet British Standard BS 5410.