LHS Plumbing & Heating Blog - Tips, Guides & Case Studies

Recently, our Gas Safe engineers completed a boiler replacement in Chingford (E4) after diagnosing a severely blocked primary heat exchanger inside an ageing Vaillant combi boiler. The customer had experienced ongoing heating issues, poor hot water performance, and rising energy bills. Following a full inspection, we recommended replacing the boiler rather than carrying out an expensive repair. A failed or heavily blocked heat exchanger filled with magnetite and scale is one

Our team was called out to a Vaillant 637 boiler breakdown in Woodford Green, issue described - load banging when the boiler was on, causing the boiler to over heat and shut down, showing various fault codes on the interface. After inspecting the boiler it was confirmed the main heat exchanger was partially blocked and filled with magnetite, sludge and scale produced by the radiators in the system. Client had two options: Flush main heat exchanger and boiler or Replace the bo