2963
The heat exchanger sensor or both supply and heat exchanger sensors are defect
Worcester Bosch Greenstar 4000 (before May 2021)
Remedy
▶ Check the flow through the appliance and the system is filled.
▶ Check for air locks in the system and purge if required.
▶ Check the heat exchanger sensor (primary thermistor) and the plug connected to temperature sensor.
▶ Check the resistance of the temperature sensor and replace if required.
▶ Check the continuity of the temperature sensor harness and replace if required.
This code also applies to: