2. Processes and functions
2-10 Defrosting Control, Outdoor Heat Exchanger Coil (Heating)
When the outdoor temperature is low, frost may form on the outdoor heat exchanger coil. When this occurred, the defrosting system operates. The microprocessor in the outdoor unit monitors the relationship between the temperature of the outdoor heat exchanger coil and the outdoor temperature so it can defrost when necessary.
Flow of Defrosting
Heating operation
No counting time for detecting frost : 15 minutes
Detecting the frost
Stand by time for defros:
25minutes
Defrosting
Release of defrosting
OUTDOOR COIL |
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TEMP. |
| C1 (°F) |
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| Y “RELEASE OF |
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| DEFROSTING” |
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50 |
| RANGE |
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| OUTDOOR AIR TEMP. | |
7.3 |
| 50 | (°F) |
| X | ||
27 |
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18 |
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| The area below the heavy line | |
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| is the frost detection area. | |
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Either continuous 8 minutes or cumulative 60 minutes are required to detect frost in the “Frosting” range.
Refer to time chart.
*Minimum continuous operating time by defrosting is 48 minutes (= 15 + 8 + 25).
Occurs either when the temperature of C1 (the outdoor 
heat exchanger coil) has reached 50°F or above,
or when the maximum defrosting time (9 minutes) has elapsed.
2 |
1143_THS_I
Time Chart for Defrosting
Fig. 13
| 1 MINUTE | MAX. 9 MINUTES | 1 MINUTE |
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COMPRESSOR | ON | ON | ON |
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SOLENOID COIL | ON |
| ON |
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(4 WAY VALVE) |
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OUTDOOR FAN | ON |
| ON |
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(H OR L) |
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INDOOR FAN |
| OFF OR LL | OFF |
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(SET SPEED) |
| OR LL |
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“STANDBY” |
| “STANDBY” APPEARS |
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INDICATOR |
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| Defrosting |
| Release of |
| Fig. 14 |
| Start |
| Defrosting | 0442_M_S |
❑During the defrost cycle, STANDBY appears on the remote controller.
❑*......Cold Draft Prevention may operate occasionally
SM830082
II - 13
