– 51 –
4. Defrost control
1) During heating operations, defrost operations are performed when the temperature from the TE sensor
satisfies any of the conditions in the A to D zones.
2) During defrosting operations, defrost will be terminated if the temperature from the TE sensor continues
at 12°C or higher for 3 seconds or if the temperature is 7°C
≤
TE < 12°C for 1 minute.
Furthermore the defrost operation will be terminated if defrosting operations have continued for
10 minutes even if TE sensor temperature is less than 7°C.
3) After defrost operations have been reset, the compressor restarts heating operations without stopping.
∗
The minimum TE value during 10 and 15 minutes after starting heating operation is stored as TEO.
–2
–5
–10
TE [˚C]
–18
Start warming operation
0
10
15
39
∗
45
55
90 [min.]
A zone
A zone
B zone
B zone
C zone
C zone
D zone
D zone
A zone
B zone
C zone
D zone
A Zone
B Zone
C Zone
D Zone
When To is normal
When To is abnormal
Status [(TEO-TE) – (ToO-To)
≥
3°C] continues for 20 seconds
Status [TEO- TE
≥
3°C] continues for 20 seconds
Status [(TEO-TE) – (ToO-To)
≥
2°C] continues for 20 seconds
Status [TEO-TE
≥
2°C] continues for 20 seconds
Status [TE
≤
23°C] continues for 20 seconds
When compressor operation status TE < 2°C is calculated for d minutes
A Zone
D Zone
B Zone
C Zone
Normal operation.
Maintain frequency of current operation.
Reduce operating frequency.
Cease reduction of operating frequency
and maintain frequency of current operation.
l
1 value (A)
SM224 Type
15.7
SM280 Type
17.6
Current (A)
l
1–0.5
l
1
D zone
C zone
B zone
A zone
¡
: Short-circuit,
×
: Open
4) The above time of d can be changed by selecting jumper [J805] or [J806].
(Setting at shipment; 90 minutes)
J805
¡
¡
×
×
J806
¡
×
¡
×
d
150 minutes
90 minutes (Setting at shipment)
60 minutes
30 minutes
5. Short interrupted operation preventive control
1) Even when a thermostat OFF signal is received from the indoor unit, the compressor may not stop
during an 8 minute period after startup in order to protect the compressor.
This operation is not an error condition.
2) When operation is terminated by using a remote controller, operation will not continue.
6. Electrical current release control
An AC current detection value from T611 on the IPDU control board is used to suppress the revolution
number of the compressor so that the input current of the inverter does not exceed a specified value.
