96
Messages on the
display
Meaning
Measure
A.20
Service interval could not be activated.
Check the time and date settings.
A.21
System pressure has exceeded maximum
pressure.
Check the safety valve and diaphragm ex-
pansion vessel.
On combi boilers: Check the plate heat ex-
changer.
Information
Message on the display
Meaning
I.56
External demand active
I.57
External blocking active
I.59
Parameters were restored (parameter set was flashed to BCU electronics module).
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.
Switch OFF the power supply.
2.
Shut off the gas supply.
3.
If the boiler needs to be removed:
■
Disconnect the balanced flue system.
■
Drain the boiler on the heating water and DHW
sides.
■
Disconnect the on-site cables/leads.
Troubleshooting
Further messages
(cont.)
6151778
Service