11-6
CONTROL SYSTEM
SM TRIO52 1-A.2 GB
11.17 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 2 to 5 Hz per minute.
HzDown2 (D2) – Compressor frequency is reduced by 5 to 10 Hz per minute.
Stop Compressor (SC) – Compressor is stopped.
The MSMP receives the protection status from each one of the indoor unit. It calculates the
overall outdoor unit protection status based on each ‘i’ indoor unit protection status weight
according to the following average:
¸
¸
¸
¸
¹
·
¨
¨
¨
¨
©
§
¦
n
weight
status
prtoction
IDU
up
round
weight
protection
ODU
n
i
i
1
11.17.1 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
CONTENTS
