Boiler displays F.73, pressure reading too low or sensor open circuit

Safety: Isolate power and allow boiler to cool before removing any hydraulic components.

• Check actual pressure: Read the mechanical gauge (if fitted). If system pressure is normal but display shows very low, suspect the sensor.
• Inspect sensor connection: Locate the water pressure sensor on the hydraulic block and ensure its electrical connector is firmly seated.
• Engineer replacement: If wiring is intact, the sensor may need to be removed, checked for blockage, or replaced. This involves draining part of the boiler and should be done by a technician.