Sharp AE-A7FHR Service Manual Download Page 11

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AYAP7FHR

3 – 3

7. CURRENT CONTROL

This system, in order to prevent overcurrent during heating operation,
controls the outdoor fan motor and changes the indoor fan motor
speed by detecting total current. When the current exceeds P2, the
outdoor fan motor is automatically turned off, and when the current
falls below P4, the outdoor fan motor is turned on.

When the current exceeds P3 and the indoor fan speed shifts down
because of cold air (5. Preheat air flow), the changes in the indoor fan
speed shifts up as follows, from "off" to "HUL", or from "HUL" to "HL".
And when the current falls bellow P5, the indoor fan speed shift up is
canceled.

8. FREEZE PREVENTIVE

When the indoor pipe temperature falls below 0

C during cool opera-

tion or dry operation, the compressor is turned off.

9. DEFROST

The defrost timer (integrating the operation time of compressor)
counts time with microcomputer during heat operation.

Frost of outdoor pipe is estimated by indoor pipe temperature (TH2),
room temperature (TH1), indoor fan speed and operation state of com-
pressor.

In the defrost operation, first the compressor is turned off, the fan
speed is set to "HUL" and the outdoor fan motor is turned off.

30 seconds later the indoor fan motor is turned off, 60 seconds later
the reverse valve is turned off, and the compressor is turned on. In the
end of defrosting, the compressor is turned off, the outdoor fan motor
is turned on, 60 seconds later the reverse valve is turned on, and the
compressor is turned on, starting heat operation. At this time, the
indoor fan motor is turned off or the fan speed is set to "HUL" if preheat
air flow function is effective.

10. DELAYED OPERATION OF THE REVERSE VALVE

the heat operation is shut down or the operating mode is switched
from heat to cool or dry, or vice versa, the reverse valve is switched
after 3 minutes.

11. TEST RUN

If the "AUX" button on the unit is pressed for 5 seconds or more during
operation, cool test operation starts. The operation LED (red) flickers
during test run.

To put the system in the heating test run mode, start the cooling opera-
tion and select the heating mode on the remote control. In cool and
heat mode continuous compressor on operation is performed. In dry
mode the operation is in dehumidifying zone. In fan only mode the
indoor fan motor runs continusly.

12. TIMER

12.1. ON/OFF TIMER

When the unit operates during one hour after the OFF-time is set, ther-
mostat setting is automatically shifted (+1digC in cool operation and
dry operation, -3digC in heat operation, 16digC - 32digC). When the
ON-timer is set in heat operation and cool operation, operation starts
before 0 to 30 minutes(depends on the room temperature) so that pre-
set temperature is obtaind at set time.

12.2. ONE-HOUR TIMER

When ONE-HOUR timer is set, the unit turns off automatically after
one hour. The one hour timer operation has priority over other time
operation, such as the TIMER ON and TIMER OFF. If the ONE-HOUR
TIMER button is pressed again during operation, the unit will operate
additionally for another one hour.

13. AUTOMATIC AIR CONDITIONING

Automatic air conditioning is selected, the operation mode and preset
temperature are set automatically according to the room temperature
on starting operation.

When DRY mode is selected by the micro computer with AUTO opera-
tion, the fan speed lamps on the indoor unit panel will indicate identi-
cally with the fan speed symbols on the remote control dispaly, as the
FAN speed setting is changed accordingly. Despite, the actual fan
speed will not change, as it is determined automatically by the micro
computer.

Outdoor
Fan motor
OFF

Indoor
Fan motor
Shift UP

Compressor
OFF

Time

Input

urrent

Current transition

6.9A

8.4A

4.4A

7.3A

3.8A