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Incorrect/no control

Incorrect or no control — Bus connection defective

Worcester Bosch · Greenstar CDi Boilers

What does Incorrect/no control mean?

The heating system is not being controlled correctly, or there is no control at all, indicating a communication problem with the devices on the bus.

Common Causes

  • Bus connection defective for the devices using the bus.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the bus connection for all connected devices.

  2. 2

    Refer to the connection diagram in your manual to ensure all connections are correct and secure.

  3. 3

    Rectify any identified interruptions or defects in the bus connection.

Browse all codes in this manual (55)
Verified technical data. Last updated: April 2026

Related Faults

1A4 E1A4 E displayed — Temperature sensor in FW 100 defective1A8 E1A8 E displayed — Bus communication error with TD 200 or heating applianceA7 EA7 E displayed — General fault in the heating appliance
Source: Worcester Bosch Greenstar CDi Boilers
Open Manual (Page 68)Search more codes in this manual