12-7
CONTROL SYSTEM
SM YBD018 1-A.1 GB
12.7
Protections
There are 5 protection codes.
Normal (Norm) – unit operate normally.
Stop Rise (SR) – compressor frequency can not be raised but does not have to be decreased.
HzDown1 (D1) – Compressor frequency is reduced by
Down1
Hz/min.
HzDown2 (D2) – Compressor frequency is reduced by
Down2
Hz/min.
Stop Compressor (SC) – Compressor is stopped.
12.7.1
Indoor Coil Defrost Protection
ICT Trend
ICT
Fast
Increasing
Increasing No
change Decreasing
Fast
Decreasing
ICT < -2
SC
SC SC SC SC
-2
ICT < 0
D1 D1 D2 D2 D2
0
ICT < 2
SR SR D1 D2 D2
2
ICT < 4
SR SR SR D1 D2
4
ICT < 6
Norm Norm SR
SR
D1
6
ICT < 8
Norm Norm Norm SR
SR
8
ICT
Normal
12.7.2
Indoor Coil over Heating Protection
ICT Trend
ICT
Fast
Decreasing
Decreasing No
Change Increasing
Fast
Increasing
ICT > 55
SC
SC SC SC SC
53 < ICT
55
D1 D1 D2 D2 D2
49 < ICT
53
SR SR D1 D2 D2
47 < ICT
49
SR SR SR D1 D2
45 < ICT
47
Norm
Norm
SR SR D1
43 < ICT
45
Norm Norm Norm SR
SR
ICT
43
Normal
12.7.3
Compressor over Heating Protection
Compressor temperature can be in one of 5 control zones (4 in protection, and 1 normal), according
to the following chart.
