Daikin 2MXS40H2V1B Service Manual page 101

SiBE121123_A
(4) Indoor Heat 1. The indoor heat exchanger thermistor is used for controlling 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
6. When only one indoor unit is operating, the indoor heat exchanger thermistor is used for
(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
Function and Control
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 thermistor 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 outdoor electronic expansion valve
openings to obtain the target subcool.
control. The actual subcool is calculated with the liquid pipe temperature and the maximum
indoor heat exchanger temperature. The system controls outdoor electronic expansion valve
openings to obtain the target subcool.
system controls 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.
Function of Thermistor
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