High Pressure Protection; Overload Starting; Defrosting; Starting Conditions Of Defrosting - Mitsubishi Electric MSZ-G09SV Service Manual

2. High pressure protection

In HEAT mode the indoor coil thermistor detects the temperature at the indoor heat exchanger and controls the compressor
operational frequency to prevent the condensing pressure from increasing excessively.

3. Overload starting

When the room temperature thermistor reads 18°C or above, the compressor runs with its maximum frequency regulated for
3 minutes after the start-up.

4. Defrosting

(1) Starting conditions of defrosting

When the following three conditions, a), b), and c), are satisfied, the defrosting starts.
a) The defrost thermistor reads -3°C or below.
b) The cumulative operation time of the compressor has reached any of the set values: 35, 40, 45, 50, 55, 60, 65, 70,
75, 80, 85, 90, 95, 100, 105 minutes.
c) More than 5 minutes have passed since the start-up of the compressor.
w Set value of compressor operation time(hereinafter referred to as defrost interval)
The first defrost interval is 32 minutes long, and the second 35 minutes long.The third and subsequent intervals are
set to be longer, and less frequent, depending on defrosting time.
The third and subsequent defrost intervals follow any of the three patterns ... 5 or 10 minutes longer, the same, or 5 or
10 minutes shorter compared with the previous defrost interval ... with the longest 115 minutes and the shortest 30
minutes.
(2) Releasing conditions of defrosting
Defrosting is released when any of the following condition is satisfied:
a) The defrost thermistor reads 13°C or above.
b) Defrosting time has exceeded 10 minutes.
c) Some other modes than HEAT mode is set during defrosting.
Time chart of defrosting in HEAT mode (reverse type)
<indoor unit>
set position
Horizontal vane
Indoor fan
<outdoor unit>
Compressor normal
Outdoor fan
R.V. coil
(21S4)
Very Low (temperature of indoor coil thermistor > 18:)
30
seconds
MAX. Hz
OFF
1 30
second seconds
5 seconds
normal
ON
horizontal
OFF
MAX. 105Hz (MSZ-G09SV)
MAX. 125Hz (MSZ-G12SV)
OFF
OFF
39
set position
set speed
MAX. Hz
OFF
30 1
seconds second
5
seconds
normal
ON