Viessmann VITOCAL 300, Installation And Service Instructions Manual

Page: 61 / 160

Fault messages Cause Measures
A9 Heat pump Heat pump or circula-
tion pump of the pri-
mary or secondary
circuit faulty Check the heat pump, the
primary pump and the sec-
ondary pump (see page 51),
and replace, if required.
The device enters emer-
gency mode with the electric
heater until the fault mes-
sage has been acknowl-
edged (heating circuits:
reduced mode, set DHW
temperature: 30 °C).
After the repair has been
carried out, the heat pump
only restarts after the equip-
ment was first turned OFF.
AB E heater The flow temperature
does not rise, the elec-
tric heater may be
faulty or the high limit
safety cut-out has re-
sponded Check the electric heater
and the high limit safety cut-
out, possibly reset the high
limit safety cut-out (see
page 63).
AC Natural cooling Faulty function As part of the relay test (see
page 79), check the natural
cooling connection exten-
sion and the continuity to the
pumps.
In case of natural cooling
with mixer; check the mixer
motor and the direction of ro-
tation.
AD Mixer
–
heating/
DHW
Three-way valve faulty Check the three-way valve
(see page 51) and replace, if
required
AF Cylinder primary
pump Cylinder primary pump
is faulty Check the pump (see
page 51); replace, if required
C1 Power supply/
compressor Compressor fuse, main
isolator, phase monitor
or motor overload
faulty Check the components and
replace them, if required.
For phase monitor descrip-
tion, see page 127
C3 Brine pressure Brine pressure too low Increase the pressure in the
primary circuit
Control unit diagnostics
(cont.)
61
Troubleshooting
55
92
901
GB
Service