Midea mcd-24hrdn1, Service Manual

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Electrical Control Function
Electrical Control System 191
When cooling, the setting temperature rises 1
℃
(be lower than 30
℃
) every one hour, 2 hours later the
setting temperature stops rising and the indoor fan is fixed at low speed.
When heating, the setting temperature decreases 1 ℃ (be higher than 17 ℃ ) every one hour, 2 hours later
the setting temperature stops rising and indoor fan is fixed at low speed. (Anti-cold wind function has the
priority).
1.3.7.3 Operation time in sleep mode is 7 hours. After 7 hours the AC quits this mode but doesn’t turns off
1.3.7.4 Timer setting is available
1.3.8 Auto-Restart function
The indoor unit is equipped with auto-restart function, which is carried out through an auto-restart module. In
case of a sudden power failure, the module memorizes the setting conditions before the power failure. The
unit will resume the previous operation setting (not including Swing function) automatically after 3 minutes
when power returns.
1.3.9 Drain pump control (For Duct & Cassette)
For 12k models:
1.3.9.1 Water level check
The water lever will be checked every 5 seconds, if the feedback signal is abnormal, it will be considered as
drain water full by the control system.
1.3.9.2 Drain pump control
If there is no water full error, the drain pump will be on when the unit is in cooling mode (including
auto-cooling and forced cooling) and dry mode. It will be off when the unit is in heating mode, fan only mode
or off state or compressor is stopped (if the pump is on before the unit is off, it will delay 2 minutes to be off).
If there is a water full error, the drain pump will be on when the error occurs. Afterwards:
If the error disappears in 2 minutes, the drain pump will work as normal state. (if it is necessary to turn off the
pump, it will be off in 2 minute delay.)
The other models:
Adopt the water-level switch to control the action of drain pump.
Main action under different condition :( every 5 seconds the system will check the water level one time)
1. When the A/C operates with cooling (including auto cooling), dehumidifying, and forced cooling mode, the
pump will start running immediately and continuously, till stop cooling.
2. Once the water level increase and up to the control point, LED will alarm and the drain pump open and
continue checking the water level. If the water level fall down and LED disalarmed (drain pump delay close 1
minute) and operate with the last mode. Otherwise the entire system stop operating ( including the pump)
and LED remain alarming after 3 minutes,
1.3.10 Point Check Function(Except 12k models)
There is a check switch in outdoor PCB.
Press the switch SW1 to check the states of unit when the unit is running.
Press the switch N times it will display the content corresponding to No. N. After getting into the check
function, it will display No. N with 1.5s, meanwhile the low bit decimal of digit display flashing, indicated to
get into the check function display. After 1.5s, it will display the content corresponding to No. N.
the digital display tube will display the follow procedure when push SW1 each time.
N Display Remark
00 Normal display Display running frequency, running state or malfunction code