Daikin CTXS07LVJU Service Manual page 71

SiUS121602E
(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 any
4. In heating operation, the indoor heat exchanger thermistor is used for heating peak-cut control.
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 control.
Thermistor
2. In heating operation, the liquid pipe thermistor is used for liquid pipes isothermal control. The
Function and Control
temperature. The system sets the target discharge pipe temperature according to the outdoor
and indoor heat exchanger temperature, and controls the 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.
of the following conditions are met in the room where operation halts, it is assumed as icing.
The conditions are
Tc ≤ – 1° C (30.2° F)
Ta – Tc ≥ 10° C (18° F)
where Ta is the room temperature and Tc is the indoor heat exchanger temperature.
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 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.
The actual subcool is calculated with the liquid pipe temperature and the maximum indoor heat
exchanger temperature. The system controls the electronic expansion valve openings to obtain
the target subcool.
system controls the electronic expansion valve opening so that the liquid pipe temperatures in
each room becomes equal.
Control Specification
59