Midea MEHS-09NIH2 Service Manual page 30

2.5
2
Medium
1.5
1
9.4.3.4 Defrosting mode
Condition of defrosting:
----T4＞0℃,
When the units are running, if the following two
items are satisfied, the units start defrosting:
The units run with T3＜3℃ for 40 minutes and
T3 keeps lower than TCDI℃ for more than 3
minutes.
The units run with T3＜3℃ for 80 minutes and
T3 keeps lower than TCDI+2℃ for more than 3
minutes.
----T4＜0℃,
st
If the 1 condition and 2
satisfied, then the program judges if T2 has
decreased more than 5℃.When T2 has
decreased more than 5℃, enter the defrosting
mode.
----No matter what value T4 is, if the machine
runs with T3＜3℃ for more than 120 minutes
and T3 keeps lower than TCDI+4℃ for more
than 3 minutes, the machine will enter
defrosting mode no matter if T2 drops more
than 5℃ or not.
Condition of ending defrosting:
If any one of the following items is satisfied, the
defrosting will finish and the machine will turn to
normal heating mode.
----T3 rises to be higher than TCDE1℃.
----T3 keeps to be higher than TCDE2℃ for 80
seconds.
----The machine has run for 10 minutes in
defrosting mode.
Defrosting action：
For 9k,12k models:
Low
High
nd
condition items are
on
Compressor
off
on
4-way valve
off
on
Outdoor fan
off
on
Indoor fan
off
Indoor fan breeze(10s)
xx=60s.
For 18k,22k models:
on
Compressor
off
on
4-way valve
off
on
Outdoor fan
off
on
Indoor fan
off
Indoor fan breeze(10s)
XX=60 for 18k model, XX=90 for 22k model.
9.4.3.5 Evaporator coil temperature
protection
----T2> TEH2℃, the compressor running
frequency decreases to the lower level and
runs for 20s.
When the frequency decreases to F2 and the
T2 is still over TEH2℃ for 3 minutes, the
28
Frequency F2 FrequencyF8
10s
xx
10s
no longer than 10m 30s
Frequency F2 Frequency F8
10s
xx
10s
30s
no longer than 10m