Heating and plumbing advice from ChauffePro

The hydraulic block connects several water-side components. A leak may require a seal or individual part rather than the entire assembly.

A pressure sensor informs the boiler controls about circuit conditions. An unusual reading needs comparison with actual pressure and the sensor circuit.

An automatic air vent removes air at a suitable point in the circuit. Leaks or recurring air need checking without confusing venting with a complete repair.

A safety valve protects the circuit from excessive pressure. Water at its outlet may reflect a valve issue or another problem causing pressure to rise.

An NTC sensor helps the boiler measure temperature. A sensor-related error can also involve a cable, connection or measurement circuit.

A boiler that lights and then stops may have a flame detection issue, but the flame itself, wiring and controls also need assessment.

An ignition electrode helps start the flame. Failed ignition may also involve the supply, wiring, gas valve, controls or combustion conditions.

The expansion vessel accommodates heating water expansion. Large pressure changes need checking alongside leaks, filling arrangements and safety valve discharge.