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What is checked during an annual boiler service?


Have you ever wondered what is checked on an annual boiler service?

Whatever the age of your boiler it will require an annual boiler service to ensure that it runs safely and efficiently.

The annual boiler service is also necessary to fulfil the conditions of the most manufacturers’ boiler warranties, both a Worcester boiler service and Vaillant boiler service are required annually for these industry-leading companies’ boilers, to ensure your guarantee is valid.

Whether you have an oil boiler service, or gas boiler service, it will usually take around an hour to complete.

The boiler service must be carried out by a Gas Safe registered heating engineer, for natural gas and Liquid Petroleum Gas (LPG) boilers, or if you have an oil boiler, a heating engineer registered with OFTEC.

Why do you need to have your boiler serviced annually?

The four main reasons for having a boiler service carried out on an annual basis are:

  1. To meet the conditions of manufacturer boiler service warranty
  2. To ensure that all your boiler components are working safely
  3. To ensure that your boiler is working efficiently and that all parts are in optimal condition
  4. To ensure your boiler is giving maximum energy efficiency savings when it runs

What should be inspected and checked in your annual boiler service?

Boiler visual inspections (to ensure that it meets current standards):

  • Water leaks
  • External damage to the boiler
  • Condition of electrics
  • Evidence of poor-quality installation.
  • Suitability of the boiler and controls for purpose
  • The proximity of combustible materials to the boiler
  • Accessibility for repair and service
  • Signs of overheating or stress

Tests to check boiler efficiency, which should be carried out according to manufacturer standards:

  • The boiler should be ignited and run, to check it is working correctly. Operating faults can also be identified at this stage.
  • The main boiler components can be checked, when the boiler casing is removed. Typically, these are; the burner, heat exchanger, main injector and the spark sensor probe.
  • Gas rate, which measures the volume of gas used by the appliance. To be correct it must be within the limits allowed in the boiler manufacturer’s standards. This test is an indication of whether the boiler is working to its optimal efficiency level.
  • Boiler tightness, which measures whether there is an escape of gas from the appliance, which could compromise safety and efficiency.
  • Flue gas analysis, which measures the combustion within the appliance. Adjustments to the boiler’s gas valve may be necessary to ensure efficient combustion. The flame picture is a visual inspection of the flames when the boiler is working, to see if its combustion is correct.

Boiler Safety Checks:

  • The boiler’s stability should be checked to ensure it is fitted correctly.
  • The boiler’s combustion and case seal should be checked, to ensure it is in optimum condition, and there are no leaks.
  • The inside of the boiler casing and any boiler components within should be cleaned before the casing is replaced.

Ventilation gas safety checks:

  • Air vents – present, suitability and condition.
  • Siting, suitability and condition of flues and chimneys.
  • Spillage Test is carried out to check for combustion products escaping from the flue, which would be a safety hazard.
  • Flue flow tightness test is conducted to ensure that the flue is working correctly and will prevent seepage of combustion products.
  • A check should also be made of the flue or chimney to establish that they dispose of combustion products safely.

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System pressure checks:
The working pressure is the normal operating pressure a component is designed to work at continuously, with an inbuilt safety margin. The working pressure is checked at three points to ensure it is correct. The points checked are the boiler, inlet burner and the gas meter. Problems with water mixing with the gas supply, wrong sized pipes, and blockages can be identified with working pressure tests.

The expansion vessels should also be checked for condition, pressure and size. If the pressure is insufficient it can be topped up.

Other system checks:
Gas meter checks are also carried out. Is the necessary emergency control valve present and easily accessible? Are the meter’s electrics correctly bonded? Is the meter fixed correctly and of a suitable type and size with the correct safety labelling? Does the emergency control valve work correctly?

A tightness test should be carried out on the complete system to ensure there is no escape of combustible products.

Where the boiler system is conventional or older, the heating engineer may need to check the heating cylinder, because the expansion vessel and pump will be situated in the vicinity. Similarly, in an older or conventional system, the burner, fan and heat exchanger may need to be dismantled, so that they can be checked. This is not usually necessary with a modern boiler unless there are potential faults flagged by the flue gas analysis test results.

A report of the checks and test carried out, and any faults found and corrected, or outstanding, should be completed. A copy of the completed report should be given to the boiler owner.

What does a boiler service cost?

So, by now you realise that there is more to a boiler service than you thought. We’re sure your next question is, how much is a boiler service? The cost of a boiler service can vary but typically it is around £85 for an annual boiler service. If you take out a boiler service plan, an annual boiler service is usually included, and the boiler service cost is likely to be less than a one-off boiler service. You will also get cover for any boiler repairs you may need that year.

Get a free annual boiler service with Hometree

An annual boiler service is offered by Hometree as part of Hometree’s boiler care plans.

The annual boiler service is carried out by competent heating engineers, certified with Gas Safe. The following boiler checks and inspections are carried out during the annual boiler service.

  • Visual checks are made to the boiler
  • The boiler is opened and inspected
  • A flue gas efficiency test is carried out
  • Ventilation gas safety checks are conducted
  • A visual check of the hot water cylinder is made
  • A system pressure check is carried out
  • Radiators are visually checked (if they require bleeding, this is completed)

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