Worcester Bosch produces the market-leading Greenstar range high quality, solidly built, high efficiency condensing boilers. All Greenstar boilers have Aluminium heat exchangers (Heat Engines) which have some advantages over Stainless Steel heat exchangers, but have one disadvantage, if not properly serviced at regular intervals a layer of aluminium oxide becomes compacted within the heat exchanger and becomes very hard to scrape away and clean.
Since the internal state of the heat exchanger is not visible Worcester Bosch has deemed that the passing of the Fan Pressure Test be sufficient to determine if full servicing is required. This is very handy, too handy sometimes as over the years the need to strip and open up the heat exchangers is not needed, but the gaskets and seals of the gas burners and heat exchangers are never inspected or changed.
The photo adjacent is a heat exchanger gasket from a Greenstar Junior Boiler which had deteriorated and was allowing heat (fire hazard) and CO to escape inside the boiler. On this type of Greenstar boiler, you can only inspect the electrodes by removing the Fan and Air/Gas Manifold.
I carry out servicing and breakdowns of Vaillant, Glow Worm, Worcester Bosch, Potterton, Baxi, Main and Boilers.
If a service is booked please remember to turn off the boiler at least 30 mins before my visit.
To maintain the boiler guarantee it is essential that the boiler is serviced annually, please make sure at the time of the visit that the Installation and service booklet has been left open, so we can record our service visit in the Benchmark section at the back. (Manufacturers will want to see this filled if on a warranty call-out).
Operate the boiler briefly to ensure it's working correctly. Electrically isolate the boiler/heating system and confirm with isolation test. Check for correct fuse rating (3 amp).
Check that any boiler safety device is operating correctly, then conduct a gas soundness test at the gas meter, checking that no leaks are present before any work is carried out, and tell you of our findings.
Remove the boiler casing, inspect internally and externally for any signs of distress e.g corrosion, water leaks or staining.
Following manufacturers instructions, clean the boiler and its components as necessary e.g Heat Exchanger's, Burner and any condensate trap. Some manufacturers insist on certain tests being carried out (Worcester want a Fan Pressure Reading) some want the combustion chamber or burner seals changed every 2-5 years, some boilers have a fault code history which we are able to bring up and take note of.
Safely reinstate the electrical supply, then check the boilers gas burner pressure, its gas rate is then taken via the gas meter and a flue-gas-analysis is carried out, the results should be within Manufacturers tolerances, thus making sure the boiler is burning gas correctly. Ensure any case seals and test points are fitted correctly.