Midea MSC-09HRDN1-QD0(E) Service Manual page 32

∆Tcon(℃)
9.7.4 Outdoor unit current control in heating mode.
Remark:
9K Model
12K Model
9.7.5 Indoor heat exchanger high temperature protection.
If T2＞60℃, the compressor will stop and not resume until T2＜48℃.
9.7.6 Defrosting mode.
1) Condition of defrosting.
Condition 1: If T4＞0℃,
When the units are running, if any one the following two items are satisfied the units start defrosting:
a)
b)
Condition 2: If T4＜0℃,
The program judges according to the condition 1, if any one of the two items are satisfied, then judges if T2 has
descended for more than 5℃, if it has the machine starts defrosting, or continues to judge T2 and will not defrost until
T2 drops more than 5℃.
Condition 3: No matter what value T4 is, if the machine runs with T3＜3℃ for more than 120 minutes and T3
keeps lower than -2℃ for more than 3 minutes, the machine will defrost, no matter if T2 drops for more than 5℃
or not.
2) Condition of ending defrosting.
If any one of following items is satisfied, defrosting will finish and the machine will turn to normal heating
mode.
a) T3 rises to be higher than 12℃.
b) T3 rises to be higher than 8℃ and remains for 80 seconds.
c) The machine has run for 10 minutes in defrosting.
J1 on
J2 on
0
I3HEAT
I2HEAT
I1HEAT
I1HEAT
5.2 A
5.2 A
The units runs with T3＜3℃ for 40 minutes and T3 keeps lower than -6℃ for more than 3
minutes.
The units runs with T3＜3℃ for 80 minutes and T3 keeps lower than -4℃ for more than 3
minutes.
on off
off on
-4 -2
comp. pause
freq. descends if curr. rises;
freq. remains if curr. descends
running normally
I2 HEAT
6.4 A
6.4 A
off
off
0
I3 HEAT
7.5 A
7.5 A
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