Outdoor Air Temperature Control; Cooling Overload Control; Freeze Prevention Control 1; Freeze Prevention Control 2 - Panasonic CS-VU9SKQ Service Manual

14.9 Outdoor Air Temperature Control


The compressor operating frequency is regulated in accordance to the outdoor air temperature as shown in the
diagram below.

This control will begin 1 minute after the compressor starts.

Compressor frequency will adjust based on outdoor air temperature.

14.10 Cooling Overload Control


Pipe temperature limitation / restriction.
Detects the outdoor pipe temperature and carry out restriction / limitation below (Limit the compressor
o
operation frequency).
The compressor stops if outdoor pipe temperature exceeds 61°C (VU9SK), 63°C (VU12, 18SK).
o
If the compressor stops 4 times in 20 minutes, Timer LED blinks ("F95" indicated: Outdoor high pressure rise
o
protection).

14.11 Freeze Prevention Control 1


When indoor heat exchanger temperature is lower than 0°C continuously for 6 minutes, compressor will stops
operation.

Compressor will resume its operation 3 minutes after the indoor heat exchanger is higher than 5°C.

At the same time, indoor fan speed will be higher than during its normal operation.

If indoor heat exchanger is higher than 5°C for 5 minutes, the fan speed will return to its normal operation.

14.12 Freeze Prevention Control 2


Control start conditions
During Cooling operation and soft dry operation.
o
During thermo OFF condition, indoor intake temperature is less than 10°C or

 Compressor stops for freeze prevention control
Either one of the conditions above occurs 5 times in 60 minutes.
o

Control contents
Operation stops.
o
Timer LED blinks and "H99" indicated.
o

14.13 Dew Prevention Control


To prevent dew formation at indoor unit discharge area.

This control will be activated if:
Outdoor air temperature and indoor pipe temperature judgment by microcontroller is fulfilled.
o
When COOL or DRY mode is operated more than 20 minutes or more.
o

This control stopped if
Compressor stopped.
o
Remote Control setting changed (fan speed / temperature).
o
Outdoor air temperature and indoor intake temperature changed.
o

Fan speed will be adjusted accordingly in this control.
Free
38°C
Limited Frequency
Outdoor air temperature
77
37°C