Freeze-Up Prevention - Daikin SkyAir RZR-P Series Service Manual

Outline of Control (Indoor Unit)
6.5

Freeze-up Prevention

Freeze-up
When the temperature detected by liquid pipe temperature thermistor (R2T) of the indoor unit
Prevention by Off heat exchanger drops too low, the unit enters freeze-up prevention operation in accordance with
the following conditions, and is also set in accordance with the conditions given below.
Cycle (Indoor
When freeze-up prevention is activated, the electronic expansion valve is closed, the drain
Unit)
pump 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-up prevention: Temperature is 30.2°F or less for total of 40 min.,
or temperature is 23°F or less for total of 10 min.
Conditions for stopping freeze-up prevention: Temperature is 44.6°F or more for 10 min.
continuously
[Conditions for starting when airflow direction is 2-way or 3-way]
Conditions for starting: Temperature is 33.8ºF or less for a total of 15 minutes or 32ºF or less for
1 minute continuously.
Function and Control
44.6ºF
32ºF
23ºF
10 min.
OR
44.6ºF
32ºF
30.2ºF
t1 t2
44.6ºF
32ºF
1 min.
OR
44.6ºF
33.8ºF
t1 t2
Freeze-up prevention operation
Forced OFF by thermostat
Freeze-up prevention operation
Forced OFF by thermostat
t3 t4 t > 40 min.
10 min.
Freeze-up prevention operation
Forced OFF by thermostat
10 min.
Freeze-up prevention operation
Forced OFF by thermostat
t > 15 min.
t3 t4
SiUS281117
10 min.
10 min.
55