If your radiators have cold patches at the bottom and you need to bleed them more regularly or your central heating system is making more noise than usual, be sure to tell your Gas Safe registered heating engineer when they come to give your boiler its annual service.
Your heating engineer can test the water in your system to see if it needs cleaning out completely or treating with chemicals. Then they can advise you of the best treatment for your system.
At Baxi we would always advise you to get your qualified heating engineer to carry out the cleaning of your heating system. Find your local Baxi installer here.