How Often Should You Service Your Boiler?

Annually is the short answer - but the reasons behind it are more interesting than the manufacturer warranty small print suggests. Here is what a service actually covers and why skipping one costs more than it saves.

Every boiler manufacturer we work with - Worcester, Baxi, Vaillant, ATAG - specifies an annual service as a condition of the warranty. That alone is reason enough for most homeowners. But the warranty is the least interesting reason to do it.

What actually gets checked

A service is not a glance and a certificate. Done properly it is a structured inspection of the things that degrade quietly between visits.

• Flue gas analysis to confirm the burner is combusting cleanly and safely
• Visual inspection of the heat exchanger and burner for corrosion or sooting
• Seals, gaskets and the condensate trap checked and cleared
• Gas pressure and flow rate verified against the manufacturer data plate
• Safety devices and controls function tested
• System pressure and expansion vessel charge checked

The flue gas analysis is the part that matters most and the part most often skipped by the cheapest quotes. It is the only way to know whether the appliance is burning safely, and it is the difference between a service and a wipe-down.

The case for not skipping a year

Boilers rarely fail without warning. They fail after a season of running slightly wrong - a partially blocked condensate trap, a burner drifting out of tolerance, an expansion vessel slowly losing its charge. Each of those is a ten minute fix when caught at a service and a cold house in January when it is not.

Commercial and rented properties

If you let a property, an annual Gas Safety Certificate is a legal requirement rather than a recommendation, and it is a separate thing from a service - though the two are sensibly done in the same visit. Commercial systems often warrant more frequent attention depending on usage and the insurer, and we will advise on that case by case.