Mitsubishi Electric Mr.Slim PKH-2FKA Technical & Service Manual page 51

3-5 Defrosting in HEAT mode
<Defrosting time chart>
Indoor unit
ON
Indoor fan
OFF
ON
Auto vane
OFF
Outdoor unit
ON
4-way valve
OFF
ON
Bypass valve
OFF
ON
Outdoor fan
OFF
ON
Compressor
OFF
(1) Start conditions
A. When all of the following conditions are satisfied, defrosting will start. However, when the bypass valve turns OFF,
defrosting starts 10 minutes later.
(a) More than seven minutes have passed since the compressor start-up.
(b) The outdoor coil thermistor reads -5°C or below.
(c) The outdoor fan motor output step is 100%
(d) Total time of compressor operation exceeds 30 minutes, and the outdoor coil temperature has fallen by 8 degrees or
more in comparison with that of 10 minutes after the compressor start-up.
NOTE: The outdoor coil temperature of 10 minutes after the compressor start-up is memorized until the defrosting
operation has ended.
B. When all of the following conditions are satisfied, defrosting will start.
(a) ~ (c) The same as above (a) ~ (c) in item A
(d) Total time of compressor operation exceeds "defrost interval".
Further information on the defrost interval is described in (3).
C. After the total time of compressor operation exceeds the defrost interval, the thermostat repeats ON/OFF 3 times.
Two minutes after the fourth "ON" of the thermostat, if the outdoor coil thermistor reads -5°C or below and the fan out-
put is 100%, defrosting will start.
NOTE: The count of the thermostat ON/OFF is cleared by the compressor-OFF command or defrosting start-up.
(2) During defrosting
Even if the thermostat turns OFF, defrosting continues.
The 4-way valve, bypass valve, outdoor fan, and indoor fan are OFF.
Defrosting
starts.
Set direction
10 degrees
(Remote controller still displays set direction.)
51
Defrosting
stops.
Set direction