Viessmann 47-819-55 - Repairs

89
Measures
Check that the cylinder flow and return are open.
Check DHW setting in commissioning assistant and
correct if necessary.
Check pump. Replace if necessary.
Pause time for DHW heating can be terminated by
mains reset.
981
System characteristics
No DHW heating
Cause
Water flow rate below minimum level
Measures
Check that the cylinder flow and return are open.
Check DHW setting in commissioning assistant and
correct if necessary.
Check pump. Replace if necessary.
Pause time for DHW heating can be terminated by
mains reset.
982
System characteristics
No central heating, no DHW heating
Cause
Circulation pump heating circuit 1 running dry
Measures
Check diaphragm expansion vessel and circulation
pump.
Repairs
!
Please note
Residual water will escape when the boiler or
one of the following components is fitted or
removed:
■
Water-filled pipework
■
Heat exchanger
■
Circulation pumps
■
Plate heat exchanger
■
Components fitted in the heating water or
DHW circuit.
Water ingress can result in damage to other
components.
Protect the following components against
ingress of water:
■
Control unit components (especially in the
service position)
■
Electrical components
■
Plug-in connections
■
Cables and leads
Shutting down the boiler
1. Turn off the power supply at the ON/OFF switch.
2. Shut off the gas supply.
Troubleshooting
Fault messages (cont.)
6221465
Diagnosis