Viessmann VITOCAL 250-A - Page 160

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F.1035 Communication fault, internal CAN bus
F.1035
System characteristics
Limited normal operation
Cause
■
Short circuit, internal CAN bus
■
Connections 72.CAN L/72.CAN H interchanged
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 the following CAN bus connections:
■
Connections X4.1 to X4.5 on the HPMU electron-
ics module
■
Connections X10.1 to X10.5 and X5.1 to X5.3 on
the EHCU electronics module
■
Connections X7.1 to X7.3 on the VCMU refriger-
ant circuit controller
■
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.
■
Shielding must be connected to CAN Ground
(GND).
■
Check cable type: Li2YCYv, twisted pair, shielded
or 2-core CAT5, shielded
■
Check cable length.
■
Check CAN L/CAN H assignment.
■
Check the position and number of terminators.
3. Replace CAN bus cable.
4. Replace HPMU electronics module.
F.1045 Fault, external heat/cooling generator 1
F.1045
System characteristics
External heat generator not ready for operation
Cause
Fault, external heat generator
Measures
1. Read out message via ViGuide or on control unit of
external heat generator.
2. Rectify fault on external heat generator.
3. Restart external heat generator.
See installation and service instructions for external
heat generator
F.1049 Malfunction, external 3/2-way mixing valve for dual mode operation
F.1049
System characteristics
External heat generator not ready for operation
Further message: A.109 if set flow temperature is not
reached within 60 min.
Cause
An external 3/2-way mixing valve for dual mode opera-
tion is malfunctioning
Messages
Fault messages (cont.)
6218234
Diagnosis