–25–
T = 17
T > 15
–3
~
~
~
~
~
~
~
~
~
2) Control at heating
1
When the compressor is stopped and during defrosting, the fan is stopped.
2
When the power is turned on, or when the compressor is restarted after being stopped for 30 minutes or longer,
the piping temperature (TH1) determines the fan step.
TH1 > 8
°
C
Fan output = 60 %
TH1
=
<
8
°
C
Fan output = 100 %
3
When the compressor is restarted within 30 minutes, the fan step is the step before the compressor was stopped.
4
When the mode is changed from cooling to heating, the fan step conforms to item
2
.
5
When returning from defrosting, the fan step is the step before defrosting.
6
Two minutes after the fan was restarted, the fan step is controlled every 30 seconds based on the piping tem-
perature (TH1).
7
When TH1 is –5
°
C or lower, the fan output is made 100 %.
• FAN step
The following expression determines the next fan step count nj+1:
nj+1 = nj+
∆
nj
nj: Current fan step,
∆
nj: Displacement step amount
nj control
• If nj+1
=
>
100 %
nj+1 = 100 %
• If nj+1
=
<
20 %
nj+1 = 20 %
• If TH1 < –5
°
C
nj+1 = 100 %
FAN
∆
nj
Outputs are all %.
(4) Defrosting control
1) When the following conditions are satisfied, defrosting starts:
1
When the integrated compressor operation time has exceeded T
1
(initial setting 50 minutes) and the piping
temperature (TH1) is below –10
°
C
2
When the integrated compressor operation time has exceeded 30 minutes and the piping differential tempera-
ture is
∆
TH1
=
>
8, TH1
=
<
–10
°
C
Piping differential temperature
∆
TH1 = TH10 – TH1
2) The defrosting prohibit time T
1
is set as following based on the defrosting time T
2
:
Note: T
1
is reset at the end of defrosting, or by cooling ON command.
Note: When the compressor was stopped during defrosting, T1 = 20 minutes is set to recognize the stop as defrost-
ing end.
3) During defrosting, all the outdoor fans are stopped and the bypass solenoid valve (SV1) is turned ON and the 4-way
valve (21S4) is turned OFF.
4) When the following conditions are satisfied, defrosting ends:
1
T
2
=
<
2 mins
TH1
=
>
20
°
C
2
2 < T
2
< 15 minutes
TH1
=
>
8
°
C continuous 2 minutes
3
T
2
=15 minutes
5) When the fan and 4-way valve (21S4) are turned ON at the end of defrosting, the heating mode is reset. Two minutes
after defrosting reset, the bypass solenoid valve (SV1) turns OFF.
Target evaporation
temperature 10
°
C
Evaporation temperature TH1
20
=
<
nj + 1
=
<
100
Current
output
T > 19
°
C
–10
T = 19
T > 17
–4
T = 15
T > 13
–2
T = 13
T > 11
–2
T = 11
T > 8
0
T = 8
T > 6
2
T = 6
T > 4
2
T = 4
T > 2
3
T = 2
T > 0
4
T
=
<
0
°
C
10
Current piping temperature
Piping temperature 10 minutes after starting or
10 minutes after returning from defrosting
T
2
=
<
3 (minutes)
T
1
60 (minutes)
3 < T
2
< 15
40
T
2
= 15
30
