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9-26. Heat defrosting control
(1) Conditions to enter defrosting mode
1
. When temperature of defrosting thermistor is -3
:
or less.
2
.When specified non-defrosting time, is counted in the control P.C. board is satisfied.
(Total time of compressor operating)
Going to defrosting mode at both condition of
1
and
2
.
(2) Defrosting operation
1
. Compressor stops for 50 seconds, indoor fan is off and defrosting lamp lights.
2
. 4-way valve reverses flow, Compressor operates by the frequency in heat defrosting control.
3
. After compressor stops for 35 seconds, 4-way valve reverses flow, then defrosting finishes.
(3) Conditions to finish defrosting mode
1
. When the defrosting thermistor temperature is 8
:
or more.
2
. When it has spent 10 minutes for defrosting.
Defrosting finishes at condition of
1
or
2
.
This protection controls the compressor ON/OFF and operation frequency according to temperature of the discharge
temperature thermistor.
(1) Compressor ON/OFF
When temperature of the discharge temperature thermistor exceeds 116
:
, the control stops the compressor.
When temperature of the discharge temperature thermistor is 80
:
or less, the controls starts the compressor.
(2) Compressor operation frequency
When temperature of the discharge temperature thermistor is expected to be higher than 116
:
, the control decreases
12Hz from the current frequency.
When temperature of the discharge temperature thermistor is expected to be higher than 111
:
and less than 116
:
, the
control decreases 6Hz from the current frequency.
When temperature of the discharge temperature thermistor is expected to be higher than 104
:
and less than 111
:
, the
control is set at the current frequency.
9-27. Discharge temperature protection control
Note
• When the indoor coil thermistor is 57
:
or more on HEAT operation, fan speed is fixed to Low.
Or, the indoor coil thermistor is 45
:
or less on HEAT operation, fan speed is back to normal.
9-28. Outdoor fan control
Fan speed is switched according to a number of operating indoor unit and the compressor frequency.
COOL
Fan speed
Up
Down
Up
Down
Single
Double
Mode
HEAT
Indoor unit operation
<Relation between compressor frequency and fan speed>
60Hz
50Hz
60Hz
50Hz
60Hz
50Hz
60Hz
50Hz
Up
Down
Fan speed
High
Low
Compressor frequency
Min.
Max.
Discharge temperature (
:
)
LEV opening
correction (pulse)
more than Target discharge temp11
Target discharge temp11 to Target discharge temp8
Target discharge temp8 to Target discharge temp5
Target discharge temp5 to Target discharge temp2
Target discharge temp2 to Target discharge temperature-2
Target discharge temperature-2 to Target discharge temperature-5
Target discharge temperature-5 to Target discharge temperature-8
Target discharge temperature-8 to Target discharge temperature-11
Target discharge temperature-11 or less
COOL
10
4
2
1
0
-1
-2
-5
-8
HEAT
8
2
1
1
0
-1
-1
-2
-6
The LEV opening is corrected according to difference between the target discharge temperature and discharge temperature.
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