B/V

▶ Check if lead is disconnected from the safety temperature limiter.
▶ Check the high limit of the safety temperature limiter and the harness for continuity.
▶ Check the flow temperature to confirm actual temperature (may have tripped out at lower temperature, leading to safety temperature limiter 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 blockage/restriction within boiler/pipe work restricting the flow.