Viessmann VITOCAL 200-G, Installation And Service Instructions Manual

Page: 117 / 208

Fault messages Cause Measures
EXT E heater The flow temperature
does not rise; the in-
stantaneous heating
water heater may be
faulty Check the high limit safety
cut-out and the heater ele-
ments; replace, if required
AC Natural cooling Faulty function As part of the relay test (see
page 131), check the natural
cooling connection exten-
sion and the continuity to the
pumps
AD Mixer
–
heating/
DHW
Mixer faulty Check the mixer (see
page 110); replace, if re-
quired
AF Cylinder primary
pump Faulty cylinder primary
pump Check the pump (see
page 110); replace, if re-
quired
B1 KM communica-
tion Communication error,
programming unit Check connections and re-
place the programming unit,
if required
BA KM BUS
mixer HC 2 Communication fault
mixer HC 2 Check the extension kit con-
nections; start the extension
kit
BB KM BUS
NC mixer Communication fault
natural cooling mixer
BC KM BUS
RC HC 1 Fault KM BUS remote
control; heating circuit 1 Check connections and
cables/leads
BD KM BUS
RC HC 2 Fault KM BUS remote
control; heating circuit 2
C1 Power supply/
compressor The compressor power
supply is not OK (e.g.
rotational direction,
asymmetrical, phase
failure). Compressor
fuse, main isolator,
phase monitor or motor
overload faulty Check the power supply and
components; replace, if re-
quired
C4 Power-OFF con-
tact Power-OFF contact en-
abled longer than 12 h Check the Power-OFF con-
tact and replace if required
Control unit diagnostics
(cont.)
117
Troubleshooting
55
92
968
GB
Service