V

If the blocking fault persists for a prolonged period, it becomes a locking fault.
▶ Check if the lead is disconnected from the safety temperature limiter/thermostat or the flue thermostat.
▶ Check the high limit of the safety temperature limiter/thermostat or the flue thermostat and the harness for continuity.
▶ Check the flow temperature to confirm actual temperature (may have tripped out at lower temperature, leading to a safety temperature limiter/thermostat or the flue thermostat fault).
▶ Check the system pressure and top up as required.
▶ Check if air is trapped in the system and in the boiler.
▶ Pump seized/not running: check the pump for failure or blockage.
▶ Check if a blockage/restriction within boiler/pipework is restricting the flow.