Boiler Maintenance Guides & Advice

Boiler maintenance advice

Your boiler is a box that brings gas, electricity and water together to heat up water for your taps and your central heating system. It works hard every day heating up and cooling down, pumping and making sure your home is warm and comfortable. There are a few simple maintenance jobs you can do yourself to keep it in tip top condition and working safely and efficiently, as well as making sure you have it serviced annually.

Look after your boiler

Keep your boiler clean by wiping the case with a soft, damp cloth and then drying it.

If your boiler is in a cupboard, be sure to allow the manufacturer's recommended clearances so it can be accessed and serviced safely. It's also crucial to keep air vents, grilles and flues free from blockages.

Do not remove the case. Only a Gas Safe registered engineer is legally qualified to remove your boiler's casing. If you think there might be a problem with your boiler, call an expert. Doing it yourself with gas is extremely dangerous and can cause leaks, fires, explosions and Carbon Monoxide poisoning.

Fit a room thermostat and set the timer

If you don't already have a room thermostat, consider having one fitted. You can expect savings of £70 and 280 kg carbon dioxide a year, according to Energy Saving Trust. Find out more from the EST website.

It is best to plan out and set the timer when you need your boiler throughout the day. This will ensure that your boiler isn't working hard when you don't need it to be. With a modern boiler, leaving the house unheated when empty and programming the boiler to start heating your home half an hour before you need it should be enough to warm your home when it matters.

Turn down the heating

Try turning your room thermostat down by one degree then leave it for a day. If you still feel warm enough, try turning it down another degree. Carry on until it feels a bit too cool and then turn it back up one degree. Every degree that you turn it down could save you around £90 a year on your heating bill.

Hot water cylinder

Your cylinder thermostat should be set at 60°C/140°F. This is hot enough to kill off harmful bacteria in the water, but use caution as it's also hot enough to scald. For extra safety, consider installing a thermostatic mixing valve which will automatically ensure that hot water at your tap is at a safe temperature.

If your tank is not insulated, you can easily lag it yourself. You can insulate the hot water pipes around it at the same time. The tank jacket and pipe insulation should cost no more than around £15, and could save you a further £35 a year.

Watch this video to find out how to replenish the air-gap on a Megaflo cylinder.

Winter advice

If your boiler has been installed with the plastic condensate pipe on an outside wall, the liquid inside the condensate pipe could freeze if the temperature drops below zero. If this happens, the boiler will shut down to protect itself and you will see the error code E133 on its display panel. The display will alternate between E1 and 33. Please watch our videos to find out how to unfreeze your condensate pipe.

Check your paperwork

Your installation manual should contain your boiler's service history. Make sure this is completed every time an annual service or work is carried out as it may be required to validate your boiler's warranty.

If your standard warranty has run out, Baxi Customer Support offers extended warranties which insure you against breakdowns. You can take out a Baxi Customer Support warranty whenever you like. If you still have time left on your original warranty, your extended warranty will automatically kick in on the day your original warranty expires.

Maintenance and Support Plans 

Whether your boiler is in or out of warranty, we can look after you.

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Annual service

The law requires that all servicing and gas safety checks are made by a Gas Safe registered engineer and an annual service can make all the difference in reliability, efficiency and household bills. If your boiler is still under warranty, having an annual service is a condition of the warranty. Always ask to see the engineer’s Gas Safe ID.

What happens at a boiler service?

The engineer will remove the boiler casing to look at its components. They will check the boiler is working safely and efficiently. A good service includes checking:

  • Correct gas pressure and flow
  • Flue and combustion. A flue gas analyser will be used to make sure the boiler is burning the right mixture of gas and air.
  • Electrical connections are clean and in good condition
  • Fans and other key components are working efficiently
  • Seals are intact
  • Electrodes are in a good condition
  • Safety devices are checked
  • Condensate trap and pipe is not blocked
  • Water and gas pipework

Pilot light

If you have an older boiler (SEDBUK Band G), you should regularly check its pilot light, a small naked flame inside the boiler that you can see through a small hole covered by glass.

Newer high efficiency boilers don't need a pilot because they have electronic ignition. This is a much safer and energy efficient way to start your boiler, and more cost effective, because you are not burning gas you can't use.

However, if you do have a pilot light, it should always burn with a bright, solid blue flame. This shows that the boiler is burning efficiently and correctly. If your pilot light burns with a yellow or orange wavy flame, the gas is not burning cleanly and this could be a sign of a carbon monoxide leak.

Boiler flues in ceiling spaces

If you live in a property that has a boiler flue which cannot be inspected because it is hidden behind a wall or ceiling, you need to install an inspection hatch.

As part of essential safety checks, gas engineers need to be able to see the flue that takes fumes away from the boiler. A flue in poor condition, combined with a boiler that is not working properly, could put you and your family in danger from carbon monoxide poisoning, which can cause death or serious injury.

If you have a boiler where the flue is completely or partly hidden, the owner of your property (whether yourself or a landlord) will need to arrange for inspection hatches or a carbon monoxide detection system to be fitted.

Carbon monoxide alarms should not be used an alternative to your Gas Safe registered engineer being able to see the flue and if you can't see the flue, you will still need to have hatches or a detection system fitted as soon as possible. From 1st January 2013, registered engineers are obligated to turn off the gas supply to any boiler systems which haven't had hatches fitted in the appropriate places.

If you have any questions or would like to find out more about flues in ceiling spaces, or visit this link, or ring 0800 408 5500.

Carbon Monoxide (CO) Advice

Carbon monoxide (CO) is a toxic gas produced by the incomplete combustion of fossil fuels including gas, oil, wood and coal used in boilers, engines, oil burners, gas fires, water heaters, gas ovens, solid fuel appliances and open fires.

It can occur when a gas appliance has been incorrectly fitted, badly repaired or poorly maintained. It can also occur if flues, chimneys or vents are blocked.

It is colourless, odourless and tasteless, so the best way to detect carbon monoxide is to fit a CO alarm.

CO poisoning

The most common symptoms of mild carbon monoxide poisoning are headache, nausea and feeling tired or confused - in fact, very similar symptoms to those of flu.

However, if you find your symptoms improve or go away when you are away from home, and get worse when you return, and if everyone else in the home, including pets, has the same symptoms, you may be experiencing carbon monoxide poisoning and should see your GP immediately.

In severe cases, it can quickly cause collapse and loss of consciousness, long term damage and even death. The Gas Safe Register website can provide comprehensive advice on what to do if you suspect carbon monoxide poisoning.

CO alarms

For you and your family's safety, it is advisable to fit a carbon monoxide alarm in each room in your home that has a gas appliance.

The Gas Safe Register recommends the use of an audible carbon monoxide alarm rather than one that just changes colour when carbon monoxide is present. It is important that it will alert you straight away or wake you up if you are asleep. The alarm should be marked with British Standard EN 50291, and a British or European approval mark such as the Kitemark.

  • Ensure your carbon monoxide alarm has a battery life of five years
  • Test your alarm weekly
  • Fitting a carbon monoxide alarm is not a substitute for having your appliances regularly serviced
  • Smoke alarms do not detect carbon monoxide
  • Don't forget to take a portable audible carbon monoxide alarm on holiday with you. Protecting the family when away is often overlooked in the rush to pack the family suitcases

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