Daikin FTXM-V Series, Service Manual

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SiUS042113E Control Specification
Part 4 Functions and Control 75
3.13.8 Target Discharge Pipe Temperature Control
The target discharge pipe temperature is obtained from the indoor and outdoor heat exchanger
temperature, and the electronic expansion valve opening is adjusted so that the actual discharge
pipe temperature becomes close to the target discharge pipe temperature. (Indirect SH
(superheating) control using the discharge pipe temperature)
The electronic expansion valve opening and the target discharge pipe temperature are adjusted
every 20 seconds. The opening degree of the electronic expansion valve is adjusted by the
following.
 Target discharge pipe temperature
 Actual discharge pipe temperature
 Previous discharge pipe temperature
3.14 Malfunctions
3.14.1 Sensor Malfunction Detection
Sensor malfunction can be detected in the following thermistor:
1. Outdoor heat exchanger thermistor
2. Discharge pipe thermistor
3. Radiation fin thermistor
4. Outdoor temperature thermistor
3.14.2 Detection of Overcurrent and Overload
Outline In order to protect the inverter, an excessive output current is detected and the OL temperature is
observed to protect the compressor.
Details  If the inverter current exceeds A A, the system shuts down the compressor.
 If the OL (Compressor head) temperature exceeds B °C (°F), the compressor stops.
SC
(S u bcooling)
SH
(S u perheating)
The target discharge pipe
temperat
u re is set as to become
the target SH.
The inclination does not change
depending on the operating condition.
(R23014)
09/12 class 18 class 24 class
Cooling Heating Cooling Heating Cooling Heating
A (A) 13.0 13.0 20 20 20 20
B (°C) 125 125 125 125 125 125
(°F) 257 257 257 257 257 257