2.2 Fault table
The red LED on the YKNOpen electronic board is responsible for showing the state of faults on the unit:
• When the red LED remains off there are no faults in the unit.
• If the red LED does two series of flashes in a constant sequence, there is a fault which must be
checked in the following table:
Fault table (red LED)
Red LED flashes
Description
1st Series
2nd Series
1, 2 or 3
1
Discharge temperature exceeded
2
High-pressure switch, outdoor fan thermal switch or compressor
module thermal switch
3
Low pressure switch
4
Indoor fan thermal switch
5
Repeated cold start-up or suction temperature < ‑25 °C
4
1
Gas control 1 or resistor 1 fault
2
Gas control 2 or resistor 2 fault
3
Resistor stage 3 fault
4
Resistor stage 4 fault
5
Fault in economiser or hot water coil (outdoor supply probe, water
return)
6
Smoke or high temperature detection (accessory) or supply tem‐
perature > 80 °C
2.3 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.
Wiring diagrams
2
Fault table
2.2
49
Summary of Contents for VCH-25A
Page 4: ...1 Installation manual...
Page 50: ...2 Wiring diagrams...
