Daikin Super multi NX E Series Service Manual page 122

Function of Thermistor
(2) Discharge 1. The discharge pipe thermistor is used for controlling discharge pipe temperature. If the
Pipe Thermistor
2. The discharge pipe thermistor is used for detecting disconnection of the discharge pipe
(3) Gas Pipe In cooling operation, the gas pipe thermistor is used for gas pipe isothermal control. The system
controls outdoor electronic expansion valve opening so that the gas pipe temperature in each
Thermistor
room becomes equal.
(4) Indoor Heat 1. The indoor heat exchanger thermistor is used for controlling the target discharge pipe
Exchanger
Thermistor
2. In cooling operation, the indoor heat exchanger thermistor is used for freeze-up protection
3. In cooling operation, the indoor heat exchanger thermistor is used for anti-icing function. If
4. In heating operation, the indoor heat exchanger thermistor is used for heating peak-cut
5. In heating operation, the indoor heat exchanger thermistor is used for detecting the
6. When only one indoor unit is operating, the indoor heat exchanger thermistor is used for
7. The indoor heat exchanger thermistor is used for wiring error check function. The refrigerant
(5) Liquid Pipe 1. When only one indoor unit is in heating, the liquid pipe thermistor is used for subcooling
Thermistor
2. In heating operation, the liquid pipe thermistor is used for liquid pipes isothermal control. The
(6) Radiant Panel 1. The radiant panel thermistors are used for calculating radiant panel surface temperature.
Thermistors
2. The radiant panel thermistors are used for detecting malfunction of the indoor electronic
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discharge pipe temperature (used in place of the inner temperature of the compressor) rises
abnormally, the operating frequency becomes lower or the operation halts.
thermistor.
temperature. The system sets the target discharge pipe temperature according to the
outdoor and indoor heat exchanger temperature, and controls the outdoor electronic
expansion valve opening so that the target discharge pipe temperature can be obtained.
control. If the indoor heat exchanger temperature drops abnormally, the operating frequency
becomes lower or the operation halts.
any of the following conditions are met in the room where operation halts, it is assumed as
icing.
The conditions are
Tc ≤ – 1° C
Ta – Tc ≥ 10° C
where Ta is the room temperature and Tc is the indoor heat exchanger temperature.
control. If the indoor heat exchanger temperature rises abnormally, the operating frequency
becomes lower or the operation halts.
disconnection of the discharge pipe thermistor. When the discharge pipe temperature drops
below the highest indoor heat exchanger temperature by more than a certain value, the
discharge pipe thermistor is judged as disconnected.
subcooling control. The actual subcool is calculated with the liquid pipe temperature and the
indoor heat exchanger temperature. The system controls the outdoor electronic expansion
valve openings to obtain the target subcool.
flows in order from the port A to detect the indoor heat exchanger temperature one by one,
and then wiring and piping can be checked.
control. The actual subcool is calculated with the liquid pipe temperature and the maximum
indoor heat exchanger temperature. The system controls the outdoor electronic expansion
valve openings to obtain the target subcool.
system controls the outdoor electronic expansion valve opening so that the liquid pipe
temperatures in each room becomes equal.
Due to structural and manufactural restrictions, the radiant panel surface temperature
cannot be controlled directly with a thermistor. Thermistors are mounted on the radiant panel
piping in order to calculate the radiant panel surface temperature.
The indoor electronic expansion valve is controlled according to the radiant panel surface
temperature.
expansion valve.
SiBE121135_A
Function and Control