have done another boiler service on Worcester Bosh combi boiler.This time as you can see the heating water was very dirty and lot of deposits where found in the Magna Clean.Condensation trap was quite dirty, power-flushing of central heating  was recommended to the customer to pro-long the life to the combi boiler and lower the heating bills.Customer has called me later, where the power-flushing on the central heating has been done and where the thermo camera has been used to demonstrate the cold spots on radiators.