
User Instructions for GECO GH21RA controller
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Page 33 Edition I
19.06.2013
Alarm 3
- Damage to fuel feeder temperature sensor
The user can force safe mode when the fuel feeder temperature sensor is damaged. Safe
mode operation will continue until the controller is turned off, or the power is cut. After one
of these events the controller returns to manual or automatic mode, determines that the
sensor is faulty, and stores this as an alarm, so the operator must force safe mode again. In
save mode, the controller will continue to operate without the fuel feeder temperature sensor.
Button
– continues operation in safe mode
Alarm 4/Note 4
- Damage to DHW/returning water temperature sensor
Stan The alarm occurs when the NTC 2.2k NTC DHW/returning water temperature sensor
is damaged or not properly connected. It occurs only when the heating configuration includes
an additional DHW/Mixer pump.
When the service parameter 'S49' = 0, the alarm is reported as AL4. After confirmation by
the user, the boiler can work in safe mode without the DHW/returning water temperature
sensor.