Diagnosis - Viessmann Vitocal 300-G BW Installation And Service Instructions Manual

Diagnosis

Measures in case the room temperature is constantly too low
Carry out the following steps to troubleshoot the problem.
1. Vent the heating circuit.
2. Check the flow rate of the heating cir-
cuit(s) concerned. Recommended
spread flow/return approx. 8 K.
3. Hydraulically balance the connected
heating circuit(s).
4. Check the outside temperature sen-
sor.
No display in the display field of the programming unit
Carry out the following steps to troubleshoot the problem.
1. Start the system with the system ON/
OFF switch (see page 106).
2. Check the fuse and replace, if
required.
3. Check whether there is voltage at the
mains feed to the control unit/PCB;
provide power if required.
5. Increase the set room temperature
for standard operation and match the
heating curves (see operating
instructions).
6. Allow heating operation via the inte-
gral instantaneous heating water
heater (accessory) (see page 107).
4. Check the plug-in and threaded con-
nections.
5. Replace the programming unit.
6. Replace the main PCB.
Troubleshooting
129