Things to Look Out For in a Boiler Service in London from Hk Boiler's blog

The flue should also be checked for blockage and corrosion. If there are any signs that the flue has been blocked by dirt, this could lead to carbon monoxide poisoning in your home, so make sure any blocked areas are cleared out immediately by calling out boiler repairs east London rather than local boiler installers. 

Things to Look Out For in a Boiler Service in London