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Building Technologies  Basic documentation LMV37.4...  CC1P7546en 
HVAC Products  28 Error code list  01.12.2009 
 
Error 
code 
Diagnostic code  Meaning for LMV37.4... system  Recommended  measures 
 
21  Safety loop / burner flange open 
Safety loop or burner flange is open → repeat standardization with safety loop closed 
 
22  Air actuator not referenced 
Air actuator has not been referenced or has lost its referencing. 
1. Check if the reference position can be approached. 
2. Check if actuators have been mixed up. 
3. If error only occurs after the start of standardization, the actuator might be overloaded and  
  cannot reach its destination. 
 
23 VSD deactivated 
Standardization was started with VSD deactivated 
→ activate the VSD and repeat standardization 
 
24  No valid operation mode 
Standardization was started without valid operation mode 
→ activate valid operation mode and repeat standardization 
 
128  Running command with no preceding standardization 
VSD is controlled but not standardized 
→ make standardization 
 
255  No standardized speed available 
Motor turns but is not standardized  
→ make standardization