7 181 465 347 (01.07)
Rectifying faults
19
A7 flashing.
Hot water NTC sensor defective
Check Action
1. B Activate menu option
Show service parameters.
B Select
.2 Hot water temp.sensor .
Is a temperature between 0. and 5.
displayed?
yes: B Is the connector for hot water NTC sensor corro-
ded
1)
, damaged or dirty? Replace affected com-
ponents.
↓2.
1) For notes, refer to Appendix.
no: ↓3.
2. B Disconnect connector for hot
water NTC sensor.
B Short-circuit the 2-pin connector
on the end of the 20-pin connector
lead assembly.
Display changes to temperature
between 100. and 95.?
yes: B Power OFF the appliance.
B Change hot water NTC sensor.
B Plug the connection wire.
B Turn ON the appliance.
A7? ↓3.
no: B Change the 20-pin connector lead assembly.
↓3.
3. Temperature between 95. and 100. is
displayed.
B Unplug the connector.
After max. 60 sec.:
Does the displayed code change
to a value between 0. and 5.?
yes: B Power OFF the appliance.
B Change hot water NTC sensor.
B Plug the connection wire.
B Turn ON the appliance.
A7? ↓4.
no: ↓4.
4. B Unplug the 20-pin connector lead
assembly from the Heatronic.
After max. 60 sec.:
Does the displayed code change
to a value between 0. and 5.?
yes: B Change the 20-pin connector lead assembly.
no: B Power OFF the appliance.
B Disconnect the boiler electrical connection.
B Change PCB control board.
B Reconnect the boiler electrical connection.
B Turn ON the appliance.
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