What an annual boiler service should include
There is a wide gap between a proper boiler service and twenty minutes with a screwdriver, and the price often looks similar. This is what the work should cover.
Combustion tested with a flue gas analyser. This is the part that cannot be faked or eyeballed. The analyser measures what is coming out of the appliance and tells the engineer whether it is burning correctly. Readings get recorded.
The gas rate measured at the meter. It confirms the boiler is getting what it needs and burning what it should.
The case off and the components inspected. Burner, heat exchanger, electrodes and seals. A visual check with the case on is not a service.
The flue checked inside and out. Terminal position, condition, and evidence of spillage.
Safety devices proved. Including the pressure relief arrangement and the controls that shut the appliance down when something is wrong.
Condensate and pressure checked, plus the expansion vessel where the symptoms point to it. A failed vessel is a common cause of pressure that will not stay put.
The paperwork completed. A service record, and the Benchmark book in the boiler manual signed. That book is what most manufacturers ask for when a warranty claim comes in.
Why the warranty depends on it
Most manufacturers make the guarantee conditional on an annual service by a Gas Safe registered engineer, recorded at the time. Miss a year and the cover can be refused later, which is usually discovered at the worst moment. Keeping the record is not admin, it is the thing that makes the warranty real.
This matters more on newer boilers with long guarantees, because there is more left to lose.
Landlords and the difference between two documents
A gas safety certificate and a boiler service are not the same thing, and being sold one as the other is common.
- A gas safety check is a legal duty for landlords. It confirms the appliance is safe and produces a CP12 record.
- A service is about condition and efficiency, and it is what keeps the warranty and the boiler alive.
A boiler can pass a safety check and still be filthy and inefficient. Many landlords want both doing on the same visit, which is sensible, but they should be quoted as what they are.
