Gas Boiler Servicing Why it is important? The heat exchanger on a gas boiler is a delicate arrangement of fins and water channels designed to extract the maximum heat from the burning gas and transfer it to the circulating water.  Should any debris collect in the heat exchanger, it could prevent the maximum heat from being extracted from the burning gas.  If debris collects or forms on the burner, it will adversely affect the combustion process which could cause dangerous Carbon Monoxide gas to form. Servicing your boiler every year ensures that it operates efficiently and safely. What is done during a service? A normal service of a gas fired boiler takes about 2 hours and involves the following: 1. Checking that the gas installation is sound and does not have any leaks. 2. Checking the condition and termination of the flue to ensure it removes the flue gasses safely to outside atmosfere without leakage inside the property or enabling any of the dangerous flue gasses to re-enter the building through openings such as windows, doors and ventilation openings.  3. Checking that the air supply to the boiler and other gas applianced are correct and unobstructed. 4. Cleaning the heat exchanger with a soft brush and vacuuming away all debris.    5. Cleaning the burner with a soft brush and vacuuming away any debris. 6. Check that the boiler is supplied with gas at the correct pressure to ensure it works correctly and that it consumes gas at a rate in accordance with the manufacturers specifications. 7. If the boiler also produces hot water on demand (Combi Boiler) the flow rate and temperature of the water produced is checked to ensure it is sufficient and safe. 8. If the central heating system is sealed, so it does not have a header tank to top up the water in the loft, it would incorporate an expansion vessel to absorb the expansion of the water when it gets hot.  This expansion vessel (normally a round red cyllinder) should also be checked to ensure it contains air at the correct pressure. When should it be done? Iis best to service it at the end of the winter so any debris that might have collected on the burner or heat exchanger does not sit in contact with the metal through all the summer months where it can cause rust to form.  End of April or May might be best. Avoid leaving it until your boiler stops working between Christmas and New Year’s Eve when the snow lies six inches deep outside.  The best is to get an engineer that maintains a database with your details and contacts you when the service is due every year at the same agreed time. What does a service cost? A service costs £70.00 and normally does not require any replacement parts.