Diagnosis - Viessmann Vitocal 300-G 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
circuit(s) concerned. Recom-
mended spread flow/return approx.
8 K.
3. Hydraulically balance the con-
nected heating circuit(s).
4. Check the outside temperature
sensor.
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 112).
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
integral instantaneous heating
water heater (accessory) (see
page 113).
4. Check the plug-in and threaded
connections.
5. Replace the programming unit.
6. Replace the main PCB.
Troubleshooting
135