Heating and plumbing advice from ChauffePro

A combi boiler’s plate heat exchanger can affect domestic hot water temperature and flow. Scaling is only one possible cause of these symptoms.

The primary heat exchanger transfers combustion heat to heating water. Deposits, leaks and poor circulation require different investigations.

The gas valve controls fuel reaching the burner. A boiler that fails to ignite needs a complete diagnosis before the valve is blamed.

A new whistle, vibration or fault before ignition may require fan checks. The error message alone does not identify a failed part.

A humming pump or cold radiators may involve circulation, air or restrictions. A diagnosis should distinguish poor water flow from a failed pump.

A combi boiler’s diverter valve directs heat towards radiators or hot water production. Faults need checking alongside the actuator, controls and heat exchanger.

A blank display or an intermittent boiler fault does not automatically mean a failed control board. Learn what a diagnosis should establish before replacement.