Malfunctions - Daikin 2MKS40G2V1B Service Manual

Control Specification
4.11.10 Disconnection of the Discharge Pipe Thermistor
Outline The disconnection of the discharge pipe thermistor is detected by comparing the discharge pipe
temperature with the condensing temperature. If the discharge pipe thermistor is disconnected,
the electronic expansion valve opens according to the outdoor temperature and the operation
frequency, and operates for a specified time, and then stops.
After 3 minutes of waiting, the operation restarts and checks if the discharge pipe thermistor is
disconnected. If the discharge pipe thermistor is disconnected, the system stops after operating
for a specified time.
If the disconnection is detected 4 times in succession, then the system is shut down. When the
compressor runs for 60 minutes without any error, the error counter is reset.
Detail Detect Disconnection
When the starting control (about 660 seconds) finishes, and the 9-minute timer for the
compressor operation continuation is not counting time, the following adjustment is made.
1. When the operation mode is cooling
2. When the operation mode is heating
Adjustment when the thermistor is disconnected
When the disconnection is ascertained, the compressor continues operation for 9 minutes and
then stops.
When the compressor stops repeatedly, the system is shut down.
4.11.11Control when frequency is changed
When the target discharge pipe temperature control is active, if the target frequency is changed
for a specified value in a certain time period, the target discharge pipe temperature control is
canceled and the target opening of the electronic expansion valve is changed.

4.12 Malfunctions

4.12.1 Sensor Malfunction Detection
Sensor malfunction may occur either in the thermistor or current transformer (CT) system.
Relating to Thermistor Malfunction
1. Outdoor heat exchanger thermistor
2. Discharge pipe thermistor
3. Fin thermistor
4. Gas pipe thermistor
5. Outdoor temperature thermistor
6. Liquid pipe thermistor
Relating to CT Malfunction
When the output frequency is more than 52 Hz, abnormal adjustment is carried out.
4.12.2 Detection of Overcurrent and Overload
Outline In order to protect the inverter, an excessive output current is detected, the OL temperature is
observed to protect the compressor.
Detail
95
When the following condition is fulfilled, the discharge pipe thermistor disconnection is
ascertained.
Discharge pipe temperature + 6°C < outdoor heat exchanger temperature
When the following condition is fulfilled, the discharge pipe thermistor disconnection is
ascertained.
Discharge pipe temperature + 6°C < highest indoor heat exchanger temperature
If the inverter current exceeds 11.5~12.5 A (depending on the model), the system shuts
down the compressor.
If the OL (compressor head) temperature exceeds 120 ~ 130°C, the compressor stops.
SiBE12-816_D
Function and Control