Installation manual
26
Refrigerant Diagram and Unit Protect Devices
GMC Board Alarm Codes (Fig. 14)
There is an LED on the GMC board that displays any board
errors. The error code can be identified from the flashing
LED using the following table. In the case of more than one
error, the error with the highest priority will be displayed
until it is resolved.
In the case of normal operation, the LED flashes at a
frequency of 0.5 Hz. In the case of an error, the LED
remains off for 4 seconds, then at a frequency of 1Hz, it
flashes a number of times equal to the error code and than
remains off again for 6 seconds. If the error code has 2
digits, the flashing is interrupted for 2 seconds between
the first and second digits.
Example: error 23: LED off for 4 seconds. 2 flashes at a
frequency of 1Hz. Off for 2 seconds. 3 flashes at a
frequency of 1Hz. Off for 6 seconds. The cycle repeats
until the LED turns off because the problem is resolved
or if an error with higher priority occurs.
To reset the unit after an error has been cleared turn off
the mains supply for 10 seconds and turn on again.
Fault Code Code Description
2 Safety Input
3 Enter Water Temperature Sensor (EWT) Failure/Out of Range
4 Actual Refrigerant Temperature Sensor BPHE (TR) Failure/Out of Range
5 Outdoor Air Sensor of GMC
6 Loss communication to NUI control
7 NUI control Room Sensor
8 Unit Capacity Mismatch
9 Flow Switch error / Water Pump
10 EEProm Corrupt
13 Loss Communication to RS485 (system configuration type 6)
14 Loss of Signal From inverter board/High Temperature Release (Thermostat on compressor: 120°±4°C)
15 Exit water Temperature Sensor (LWT) Failure/Out of Range
17 Inverter Air Sensor (TO) Failure/Out of Range
18 G-Tr inverter short circuit protection
20 Compressor position Detection Circuit error
21 Inverter Current Sensor error
22 Heat Exchanger Sensors (TE) / (TS) Failure/Out of Range
23 Discharge Temperature Sensor (TD) (TD > 100° ± 4° C)
24 Outdoor Fan motor error
26 Other inverter board error
27 Compressor Lock
28 Discharge Temperature error Failure/Out of Range
29 Compressor Breakdown