The short answer
A new oil boiler should be fitted by an OFTEC registered technician, who surveys the property, sizes the boiler to the heat loss, checks the tank and supply line, fits and commissions the boiler, records a combustion reading and registers the work so you receive the compliance paperwork. Jamie Crawford Heating is OFTEC registered and handles oil installations across the areas listed on this site.
Why the installer's registration matters
Oil installations in England come under the Building Regulations. A registered competent person can self certify the work, which means you do not need to arrange a separate building control inspection. The certificate is worth keeping with the house deeds, because a buyer's solicitor will usually ask for it when the property is sold.
You can check any installer on the public OFTEC register before booking. If a quote comes from someone who cannot show a registration number, treat that as a warning sign rather than a saving.
The survey: what gets looked at before a quote
A proper survey takes in far more than the boiler cupboard. The installer needs to understand how the house loses heat, how hot water is produced and where the flue can legally terminate. Oil flues have clearance rules from windows, doors, boundaries and eaves, and a boiler that suited the old layout may not suit the new one.
- Room count, radiator sizes and hot water demand
- Whether the home suits a combi, system or regular oil boiler
- Internal or external boiler position and flue route
- Condition, age and siting of the oil tank and bund
- Supply line route, fire valve and filter arrangement
- Condensate drainage route for a condensing boiler
The tank is part of the decision
Many oil boiler replacements turn up a tank that is also near the end of its life. Older single skin tanks do not meet current expectations near watercourses, drains or buildings, and a brittle or rusting tank is a pollution risk. If the tank needs attention, it is usually cheaper and less disruptive to plan both jobs together rather than draining and reconnecting twice.
If the tank is sound, the installer should still check the supply line, fit a new filter and confirm the fire valve works, because a new boiler will not tolerate the sludge or air an old line may carry.
On the day of installation
The heating system is drained, the old boiler disconnected and removed, and the new boiler positioned and connected to the heating, hot water, oil supply and electrics. The system is refilled, flushed where needed and treated with an inhibitor to protect it from corrosion.
Commissioning is the part people rarely see but matters most. The burner is set up with the correct nozzle and pump pressure, a combustion analysis is taken and recorded, and the controls are tested. You should be shown how to use the programmer and thermostat before the engineer leaves.
How to prepare your home
Clear the area around the boiler and the route to it, and make sure the installer can reach the tank. Keep enough oil in the tank for commissioning. If you have pets, plan for doors being open while the old boiler comes out. Let the installer know about any radiators that have always run cold, since that is easier to deal with while the system is drained.
After the installation
Keep the commissioning record, the registration certificate and the manufacturer's warranty paperwork together. Most manufacturer warranties depend on the boiler being registered and serviced once a year, and oil boilers in particular benefit from an annual service because nozzles, filters and combustion settings drift over a heating season.
Frequently asked questions
Do I need an OFTEC registered installer for a new oil boiler?
It is the straightforward route. A registered technician can self certify the work under the Building Regulations, so you avoid arranging a separate building control inspection and you receive the paperwork a future buyer will ask for.
Can an oil boiler go outside?
Yes. External oil boilers are a common choice where there is no space indoors, provided the position meets the flue and access rules. The survey confirms whether it suits your property.
Should I replace my oil tank at the same time?
Only if the tank needs it. If the survey finds an old single skin tank, a damaged base or poor siting, doing both together avoids draining and reconnecting the supply twice.
Which oil boilers do you fit?
Worcester Greenstar and Grant Vortex are among the oil ranges listed on this site. Jamie Crawford Heating is a Worcester Bosch Accredited Installer.
Related pages
Arrange an oil boiler survey
Based at 24 Bristol Rd, Radstock BA3 3EE. Open Mon–Fri 8:30am–5:00pm.