Viessmann VITOCAL 250-A - Page 113

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F.519 Communication error, BACnet
F.519
System characteristics
No communication with building management system
Cause
Internal fault on gateway (BACnet/IP)
Measures
1. Check system configuration for gateway: CAN bus
subscriber number 90
2. Turn off the ON/OFF switch on the indoor unit. Wait
at least 2 min. Turn on the ON/OFF switch.
3. Replace gateway.
F.520 Communication error, Modbus
F.520
System characteristics
Refrigerant circuit off
Cause
Communication error between VCMU refrigerant circuit
controller and inverter
Measures
1. Turn off the ON/OFF switch on the indoor unit. Wait
at least 2 min. Turn on the ON/OFF switch.
2. Check LEDs on inverter:
■
Left LED is off: Check inverter power supply.
■
Right LED flashes green: Check Modbus connec-
tions X11.1 to X11.3 on the VCMU refrigerant cir-
cuit controller and X1.5 to X1.7 on the inverter:
–
Check wires and plugs for correct seating.
–
Check connections for contact corrosion.
–
Check cables for mechanical damage, e.g.
crushing, kinking, chafing or breakage.
3. Check the following connections:
■
All cables connected to the inverter
■
Connections X1.3 to X1.4 on the inverter
■
All cables connected to the compressor
■
Check wires and plugs for correct seating.
■
Check connections for contact corrosion.
■
Check cables for mechanical damage, e.g. crush-
ing, kinking, chafing or breakage.
4. Check the compressor power supply.
5. Replace VCMU refrigerant circuit controller.
6. Replace inverter.
F.544 Lead break, flow temperature sensor HC 2
F.544
System characteristics
Mixer closes. Heating circuit pump is operational.
Cause
■
Lead break, flow temperature sensor, heating/cooling
circuit 2 with mixer
■
Incorrect configuration during commissioning
Measures
1. Check configuration. Adjust settings if required.
2. Check connection X17.1/X17.2 on the EHCU elec-
tronics module:
■
Check wires and plugs for correct seating.
■
Check connections for contact corrosion.
■
Check cables for mechanical damage, e.g. crush-
ing, kinking, chafing or breakage.
3. Check resistor R for NTC 10 kΩ on the disconnected
plug. If R > 300 kΩ, replace the sensor.
4. Replace EHCU electronics module.
Messages
Fault messages (cont.)
6218234
Diagnosis