With servicing requirements often varying between different boiler manufacturers, Martyn Bridges, Director of Technical Communication and Product Management at Worcester, Bosch Group, offers a reminder of the four common checks that should make up at least part of any annual boiler service:

1: The water

One of the biggest potential contributors to the efficiency (or inefficiency) of a boiler is the quality of water within the heating system. Given how common it is for a 40-50 year old heating system to have had three or four boilers connected to it over this period, the first priority should always be to ensure the heating system water is clean and has a corrosion inhibitor added to it. This should really be an annual check to make sure the system is not corroding and still has enough inhibitor within.

2: The appliance

The next step is to look at the working of the boiler itself. Heating engineers should be making sure that the combustion efficiency of an appliance reads as per the manufacturer’s instructions – ideally once a year. Any excess or insufficient air going into the boiler will affect the efficiency of the burner, so the CO/CO2 ratio of the flue gases must be measured and the appliance adjusted accordingly. After the combustion settings have been verified, installers must then establish that the heat exchanger is free of any surface debris or contamination that could affect the transfer of heat. This can be a visual check or alternatively some manufacturers have an air pressure check requirement over the inlet and outlet of the heat exchanger.

3: The controls

Once it has been established that the boiler and the water within it are spick and span, continued efficiency then falls down to things such as controls and the balancing of the heating system.

Installers should therefore be looking to make sure their customers’ heating systems are equipped with the most effective controls. Any control system should obviously time the on/off periods, with a room thermostat turning the boiler and pump off when the desired room temperature has been achieved. With condensing boilers, a further level of weather and/or load compensation controls should help the appliance to condense as much as possible.

4: The parts

Manufacturers use a range of different components within their appliances, all of which have different parameters – a bit like the servicing requirements of a Volkswagen compared to a BMW.

Installers should therefore be on the lookout for any ‘anniversary part changes’ – proactive replacement of certain aging components that will keep the boiler ticking along nicely. This could involve changing anything from a seal to an electrode every year or two years, and can be determined by referring to the manufacturer’s guidelines.

We may still be some way away from seeing an annual boiler service made mandatory, but there is little more important when it comes to ensuring the continuity of use, safety and efficiency of a heating system.