York ACTIVA 100, Installation Manual, Page: 60 / 67

4.3 Incidents
The green LED on the YKNOpen electronic board is responsible for showing the state of incidents on
the unit:
• If the green LED flashes in a constant sequence, there are no incidents in the unit.
• If the green LED does three series of flashes in a constant sequence, there is an incident which must
be checked in the following table:
N O T E
The first series indicates the affected circuit: one flash for the first compressor, two for the second,
three for the third and four for miscellaneous incidents. A short pause follows. The second and third
series specify the direct cause of the incident.
INCIDENT TABLE (GREEN LED)
Green Led flashes Description
1st Ser‐
ies
2nd
Series
3rd
Series
Type Incident
1, 2 or 3
1
1
Probes
Discharge probe open or short circuited
2 Liquid probe open or short circuited
3 Suction probe open or short circuited
2
1
Temperature
Repeated defrosting
2 The discharge temperature is not recovered
4
1
1
Probes
Supply probe open or short circuited
2 Return probe open or short circuited
3 Outdoor probe open or short circuited
4 Water probe open or short circuited
5 Fault in the enthalpy probes
2
1
Thermostat
Signal Y1 or Y2 without signal G
2 Signal W without signal B
3 Signal W without signal G
4 Signal Y2 without signal Y1
3
1
Auxiliary heat
Heating element thermal switch 1
2 Heating element thermal switch 2
3 Heating element thermal switch 3
4 Heating element thermal switch 4
4
1
Temperature
The water coil temperature is not recovered
2 Outdoor temperature too low
3 Water coil performing antifreeze operation
4 Supply temperature above 55 °C
5 Supply temperature < 25 °C with gas
5
1
Others
Transceiver ID unknown
2 There is at least one accessory not found
3 Air quality demand
4 Dirty filters
5 Presence sensor is unoccupied
6 Suction temperature < 0 °C, economiser
Wiring diagrams 4
Incidents 4.3
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