User Instructions for GECO GH21TA controller
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Page 33 Edition I
19.06.2013
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.
When parameter
'
S49
'
= 1, note UW4 occurs, then the controller switches to safe mode and
the boiler operates without the
DHW/returning water temperature sensor.