Viessmann VITOCAL 300, Installation And Service Instructions Manual

Page: 62 / 160

Fault messages Cause Measures
C4 Power-OFF con-
tact Power-OFF contact en-
abled longer than 12 h Check the Power-OFF con-
version kit (accessory) and
replace it, if required
C8 Safety chain Fault at one of the con-
nected components Check the external safety
chain, connected compo-
nents and circuits
The flow switch has re-
sponded (flow rate too
low) Primary pumps:
Check the circulation pump
for the brine circuit or the
submersible pump
C9 Refrigerant cir-
cuit Safety high pressure
limiter has responded Check the flow and return
temperature sensors,
check the primary and sec-
ondary circuits for pressure
and throughput; ask your
local refrigeration engineer
to check the heat pump, if re-
quired
CA Primary pump Thermal overload relay
of the primary pump
has responded Reset the thermal overload
relay, check the primary
pump (see page 50) and re-
place it, if required
CB Primary tempera-
ture Primary inlet tempera-
ture below its minimum
level Check the brine circuit for
throughput
D1 Compressor The thermal overload
relay of the compressor
has responded Reset the thermo-relay,
check the setting, perform a
reset, check the connection,
check the coil resistance,
adjust the phase sequence
at the compressor.
D3 Low pressure 1 Primary circuit leaks or
primary pump faulty Reset the pressure switch.
Check the pressure gauge,
primary pump and shut-off
facilities.
Intermediate circuit
leaks or intermediate
circuit pump faulty Check pressure gauge and
intermediate circuit pump
Heat pump faulty Have the heat pump tested
by a refrigeration engineer
Control unit diagnostics
(cont.)
62
Troubleshooting
55
92
901
GB