Viessmann Heat Pump Error Codes

Complete diagnostic guide for Viessmann heat pumps (Vitocal) in the United Kingdom.

Flow and Circulation Errors

Error codes for Viessmann heat pumps related to flow, circulation and pump problems.

Error Code	Meaning	Possible Causes	Solutions
07	Flow monitor error	Defective flow monitor Bridge not removed at connections X3.3/X3.4 Circulation pump between heat pump and storage tank not working Insufficient flow in system Blocked or contaminated filter	Check circulation pump between heat pump and storage tank for function Remove bridge at connections X3.3/X3.4 if present Check flow in system Check filter for blockages or contamination and clean Test flow monitor function Replace flow monitor if defective Restart system after repair

Refrigerant Circuit and Compressor Errors

Error codes for Viessmann heat pumps related to refrigerant circuit and compressor problems.

Error Code	Meaning	Possible Causes	Solutions
A9	Refrigerant circuit error	Problems in refrigerant circuit Refrigerant leakage Insufficient refrigerant amount Problems with compressor Defective refrigerant circuit components	Read error history of refrigerant circuit controller Check refrigerant circuit for leaks Check refrigerant amount (only by qualified service) Test compressor function Check refrigerant circuit components for damage Contact qualified service for complex problems
9E	Inverter supply voltage error	Inverter supply voltage too low or too high Compressor supply voltage faulty Electrical connection problems Defective inverter Problems with power supply	Have inverter supply voltage checked by qualified service Check compressor supply voltage Check electrical connections for proper connection Check power supply Test inverter function Have inverter replaced by qualified service if defective

Temperature and Sensor Errors

Error codes for Viessmann heat pumps related to temperature sensor and overheating problems.

Error Code	Meaning	Possible Causes	Solutions
E0	Temperature sensor error	Temperature sensor defective Sensor not properly connected Cable connection interrupted Short circuit in wiring Sensor damaged	Check wiring to sensor for damage Check connector for proper connection Test sensor with multimeter Inspect sensor for visible damage Replace sensor if defective Restart system after repair
E1	Flow temperature too high	Flow temperature above maximum allowed Insufficient flow Blocked heat exchanger Problems with control	Check flow temperature and reduce if necessary Increase flow rate in system Check heat exchanger for blockages Check control settings Bleed system
E2	Return temperature too high	Return temperature above maximum allowed Insufficient flow Problems with heating circuit control Blocked heating circuit	Check return temperature Increase flow rate in heating circuit Check heating circuit control Check heating circuit for blockages Bleed system
E3	Outdoor temperature sensor error	Outdoor temperature sensor defective Sensor not properly connected Cable connection interrupted Sensor damaged or wet	Check outdoor temperature sensor for damage Check wiring for proper connection Check sensor for moisture Test sensor with multimeter Replace sensor if defective
E4	Overheating protection activated	System detected overheating Insufficient flow Blocked heat exchanger Problems with cooling	Allow system to cool down Check and increase flow rate Check heat exchanger for blockages Check cooling system Contact qualified service if problem persists

System and Communication Errors

Error codes for Viessmann heat pumps related to system errors and communication problems.

Error Code	Meaning	Possible Causes	Solutions
F0	Communication error	Communication error between components Defective control board Problems with data transmission Incompatible firmware	Check control board for errors Check communication connections Check firmware version and update if necessary Restart system Contact qualified service if problem persists
F1	System error	General system error Defective control board Problems with system configuration Hardware error	Restart system Check control board for errors Check system configuration Contact qualified service if problem persists

Need More Help?

If you are experiencing problems with your Viessmann heat pump that are not covered by these error codes, or if the provided solutions do not resolve your issue, we recommend:

Consult your Viessmann heat pump user manual for model-specific information
Contact Viessmann customer service in the United Kingdom for technical support
Use the ViCare app for monitoring and error reporting
Seek help from a qualified heat pump repair technician
Check warranty coverage if your heat pump is still under warranty

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