Freeze Prevention - Daikin RTSQ20PY1 Service Manual

SiBE31-801_C
9.4

Freeze Prevention

Freeze When the temperature detected by liquid pipe temperature thermistor (R2T) of the indoor unit
heat exchanger drops too low, the unit enters freeze prevention operation in accordance with
Prevention by Off
the following conditions, and is also set in accordance with the conditions given below.
Cycle (Indoor
When freeze prevention is activated, the electronic expansion valve is closed, the drain pump
Unit)
turns ON and the fan tap is fixed to L airflow. When the following conditions for stopping are
satisfied, it returns.
Conditions for starting freeze prevention: Temperature is -1°C or less for total of 40 min., or
temperature is -5°C or less for total of 10 min.
Conditions for stopping freeze prevention: Temperature is +7°C or more for 10 min.
continuously
[Conditions for starting when airflow direction is two-way or three-way]
Conditions for starting: Temperature is 1ºC or less for a total of 15 minutes or 0ºC or less for 1
minute continuously.
Function
+7ºC
0ºC
–5ºC
10 min.
OR
+7ºC
0ºC
–1ºC
t1 t2
+7ºC
0ºC
1 min.
OR
+7ºC
+1ºC
t1 t2
Outline of Control (Indoor Unit)
Freeze prevention operation
Forced OFF by thermostat
Freeze prevention operation
Forced OFF by thermostat
t3 t4
t >40min.
Freeze prevention operation
Forced OFF by thermostat
Freeze prevention operation
Forced OFF by thermostat
t3 t4 t >15min.
10 min.
10 min.
10 min.
10 min.
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