Boiler Servicing Cost

NV Plumbing & Heating provide all levels of boiler servicing in Blackheath, SE3 and other South East London areas. Our fully qualified, Gas Safe expert engineers and plumbers offer professional, high quality boiler servicing that caters for all needs. Whatever the make of your boiler; whether you require a standard or full service, we deliver reliable and safe boiler servicing in Blackheath and nearby. Give us a call today. We are here to help.

The importance of boiler servicing

All boilers should be serviced once a year to ensure they are functioning correctly and SAFELY. A boiler manufacturer will invalidate a warranty if the boiler is not serviced annually while under warranty. Some new boilers provide up to 12 years warranty, however, it is essential to maintain that warranty with an annual service and avoid expensive repairs.

Boiler servicing cost and what is included

Many companies service boilers for a fixed price; often a lower price than Gas Safe registered heating engineers advertise. Why? The simple answer is: because they only do a standard service or 30-minute safety check. We are not saying that a minor service is not suitable for your boiler but we recommend a full service at least every 5 years. We have seen boilers with long service histories where the combustion chamber has never been opened and electrodes and seals have deteriorated. Best practice is always to follow manufacturer’s instructions. Please note: our check list is based on Vaillant condensing boiler recommendations and may vary for other boiler manufacturers.

Standard service starting at £85+VAT Full service starting at £120+VAT
Gas tightness test All standard servicing checks +
Visual inspection Expansion vessel
Gas pressures (inlet/working) Clean the heat exchanger
Combustion performance Check and clean the burner
Condensate siphon Check ignition electrodes
Central heating filter (if fitted) Adjust the CO2 concentration if required
Safety devices CO, CO2, CO/CO2-values (again after servicing)

When booking a boiler service please provide the boiler make and model as servicing costs may differ depending on the boiler make, model and level of service require.

Different types of boiler service

Some older non condensing boilers are simpler in design and the servicing process is the same every year, unless parts needs to be replaced. Servicing this type of boiler can easily be done in 1 hour. Similarly, a standard annual service on a new condensing boiler will only take 1 hour. When it comes to fully servicing a condensing boiler and carrying out all the necessary safety checks, it is definitely not a 30-minute job! It usually takes between 1-2 hours and depending on the make of boiler, often requires replacing seals.

Standard boiler servicing

This includes:

Gas tightness test

Full gas system soundness test to confirm no gas leaks in the property. For landlords, it is a legal requirement to have a gas tightness test as a part of the safety check. For private properties, this may be the only time you have Gas Safe registered engineer in your home. At NV Plumbing & Heating, our boiler servicing engineers in Blackheath always conduct this test.

Visual inspection

Check the flue installation for any signs of leaks and for proper fixation and ensure it is not blocked or damaged and is fitted correctly, complying with the relevant boiler installation instructions. Carry out a general inspection of the boiler for dust and dirt - clean as necessary. Visually inspect the complete heat engine of the boiler for its condition and for signs of corrosion, sooting or other forms of damage.

Gas pressure

Check the gas inlet working pressure operation with boiler at maximum load. Measure the gas flow rate during operation with maximum load.


Check combustion by measuring CO, CO2 and CO/CO2. Combustion analysis will show if the boiler is operating corectly when burning gas. If this check fails, a full boiler service will be required and fault investigation if full servicing does not rectify the problem. Fault finding is NOT part of the boiler servicing process.

Other checks

These include: fully testing safety devices, checking the condensate siphon in the boiler and cleaning and re-filling it (if needed), plus conducting an annual check and clean (where necessary) of the central heating filter protecting the boiler from sludge.

Full boiler servicing

To complete a full boiler service takes between 1-2 hours depending on the boiler make and model. All checks on the standard boiler servicing list will be carried out plus:

Expansion vessel

This is an extremely important part of the boiler and the rest of the central heating system, very often overlooked by heating engineers leading to boiler breakdowns and repairs which could be avoided. This check requires draining the boiler.

Heat exchanger & burner

Check the integrity of all combustion circuit seals, especially the burner door seal. If there is any damage, replace it. Clean the heat exchanger. Check whether the burner is dirty and clean it if necessary. This check involves breaking the integrity of the combustion chamber and depending on the boiler make and model, replacing seals may be necessary.

CO, CO2, CO/CO2-values

If there are problems with the CO, CO2, CO/CO2-values in the combustion test before full servicing which are still a problem after servicing, an adjustment can be made following the manufacturer's instructions to ensure safe boiler operation.

This checklist is based on the Vaillant condensing boiler manual. Other boilers could have slightly different guidance. While booking a boiler servicing, the heating engineer should be provided with the boiler make and model to ensure that relevant seals (if needed) are availabe during servicing.

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