Oil boilers

Oil boilers in Surrey: servicing, repairs and replacement

Who this is for

Large parts of rural Surrey are not on the mains gas network. Villages and outlying properties around Cranleigh, Chobham, Worplesdon, Dorking and the lanes towards Hambledon and Hascombe frequently run on oil, and often will for the foreseeable future because extending a gas main to a handful of properties is rarely economic.

Oil heating is a different discipline from gas. Different qualifications, different servicing, different faults. We handle it as routine work rather than subcontracting it, which matters when your options are limited to begin with.

Why oil boilers need servicing more than gas

An oil boiler burns a liquid fuel through a nozzle at pressure. That nozzle is a precision component with a very small orifice, and it degrades. Combustion produces soot which fouls the heat exchanger. The fuel itself can carry water and sediment picked up in the tank.

Because of all that, an annual service is not optional maintenance — it is what keeps the appliance burning correctly and efficiently. A neglected oil boiler sootss up, loses efficiency measurably, and eventually locks out.

A proper oil service includes replacing the nozzle, changing the fuel filter, cleaning the combustion chamber and heat exchanger, checking and setting the electrodes, testing the photocell, performing a smoke test and a full combustion analysis, and checking the tank, the line and the fire valve.

Common oil faults

Lockout after a cold night. Kerosene can form wax at low temperatures, particularly in an outdoor tank with a long exposed line. The result is starvation and a lockout.

Repeated lockouts through the season. Usually a degraded nozzle, a dirty filter, or water in the tank.

Smoke or soot on start-up. Combustion is out of adjustment and the boiler is wasting fuel every minute it runs.

Smell of oil. Never ignore it. A weeping line, a failing seal or a tank problem all present this way, and there is an environmental liability attached to a spill.

Your tank matters as much as your boiler

Single-skin steel tanks corrode from the inside and eventually fail. Plastic tanks degrade under ultraviolet light and can split, usually at a seam. A leak is not merely inconvenient: heating oil contaminating soil or a watercourse is a pollution incident with the clean-up cost falling on the property owner.

Modern practice is a bunded tank — a tank within a tank — so that a failure of the inner vessel is contained. Regulations also govern how close a tank may sit to a boundary, a building or a drain. We check the tank, the base, the line and the fire valve at every service, and we will tell you plainly if yours is approaching the end of its life.

Replacing an oil boiler

Modern condensing oil boilers are substantially more efficient than the units they replace, and where the existing appliance is fifteen or twenty years old the saving over a winter is significant.

Internal or external siting each have their merits. External units free up space and move the noise outdoors but need weather protection and a frost strategy. Internal units need a flue route and adequate ventilation.

Oil, LPG, or a heat pump?

Off the gas network the comparison is genuinely open, and we have no reason to push you one way.

Oil has a low cost per unit of energy and high output, suiting large, hard-to-heat rural properties. It requires a tank, deliveries and more servicing.

LPG is cleaner and burns in a boiler very similar to a gas one, but costs more per unit and still requires a tank.

A heat pump removes fuel deliveries entirely and is the cheapest to run of the three if the property is well insulated and the radiators are sized for a lower flow temperature. In a large, draughty, solid-walled house it will disappoint, and we will say so rather than sell it to you.