Top four oil boiler problems - and how to fix them

Oil boilers are the most popular form of heating for properties that do not have mains gas and are also one of the most efficient alternatives. Thanks to constantly improving technology, they are also more reliable than ever - but like any machine that is always in use, they can encounter problems from time to time. Read on to discover some of the most common oil boiler issues and how to fix them.

1. Oil boiler won’t start

If your oil boiler won’t start (often called boiler lockout), the first thing you should do is check your tank for availability of heating oil. You may have run out and not realized, especially as we come to the end of winter when your heating has been in high demand. If you’ve run out of oil, it is advised to arrange for a delivery from your oil supplier as soon as possible, as allowing your tank to stay empty can lead to problems. To help protect your boiler, it is likely that the automatic shut-off has activated.

Once you have fuel, follow the manufacturers reset instructions to fire up the boiler again. This is usually a square red button on the side of the burner and should not require more than a couple of attempts.

If the boiler still fails to restart, check if the fuse appears to have blown and replace it with a fuse of the same rating if necessary. If the boiler still doesn’t start and you’ve followed all the troubleshooting steps in your handbook, then it is recommended that you seek assistance from a trusted engineer.

2. Your oil boiler is running but not heating

If your oil boiler is running but not heating, this may be due to a clogged burner nozzle. The nozzle has an extremely small opening that can become obstructed with mineral deposits or dirt, due to age or contaminated oil. As a rule, your oil boiler nozzle should usually be replaced annually, and is included in an oil boiler service.

To help avoid sediment in your tank causing damage to your boiler, try to keep it filled up as this will help to avoid disturbing any sediment that has gathered in the bottom. It is also worth regularly testing for water in the tank, especially if you are using an older tank, as this can be very harmful to your boiler. If in doubt, contact your boiler engineer.

3. The boiler is producing smoke and/or soot

A smokey or sooty boiler may be due to a clogged flue pipe or cracked heat exchanger. We recommend that you inspect the flue pipe, especially where it connects to the chimney, and remove any dirt and debris that may have clogged the pipe. It is also worth checking the gaskets around the inspection door. If they are warped or you detect cracks, this allows heat and smoke to escape from the furnace. You should arrange to have faulty gaskets replaced. If there is no visible cause for smoke or soot, consult an engineer.

4. Not enough heat

If your boiler seems to be running properly but is not producing enough heat and you are happy that the thermostats are correctly set, it may be due to a dirty air filter. It is quite common for lint to gather on air filters and this can cause them to become blocked if it is allowed to accumulate.

There is also a possibility that your fan belt may have broken. If the filter and fan belt appear to be in good condition, check that the supply air fan is working properly. Consult your oil boiler handbook before attempting to do any maintenance and always follow the instructions. Get in touch with an oil boiler engineer if necessary.

Most oil boiler problems can be completely avoided with an annual boiler service. Check out oil boiler care plans and pricing to learn more.

For all of your oil boiler installation and service requirements, get in touch with D.R. Plumbing & Heating today on 01978 291 923 / 01352 620 125 for expert advice or a free, no-obligation quotation.