12-9
CONTROL SYSTEM
SM OU12HP 2-E.2 GB
# Shutdown Reason
Shutdown
procedure
1 IDU NLOAD=0 (or IDU protections) Gradual Minimum On time is kept.
2 IDU Shutdown (idle) Immediate
3 Deicing Immediate
4 ODU Protections Gradual
5 Sensor faulty (CTT or OCT+OMT) Immediate
6 HPS protection Immediate
7 LPS protection Gradual (Only in 6HP units)
12.5.3 EEV Control
12.5.3.1 EEV General Rules
The EEV is controlled to keep the discharge superheat temperature within preset control
values.
12.5.3.2 EEV initialization procedure
After power up the EEV performs initialization procedure while it closed completly and reopened
to predefind position. During initialization, the compressor is forced to off.
12.5.3.3 Balance time
During the first minutes after SB the correction is not calculated. After that the correction value is
updated every EEVCVTConst seconds.
12.5.3.4 Operation Range
The EEV operation range is defined according to the operation mode as following
ODU Mode Normal operation Notes
SB 450
May change
according to model
COOL 60 to 480
HEAT 60 to 480
12.5.3.5 EEV initial value determination (EEV
OL
)
The EEV initial value (open loop) is determined according to the operation mode, the actual
frequency and ODU model. The values are determined according to the “EEV
OL
Parameters
Table”.
12.5.3.6 EEV opening determination in normal run mode
The target EEV value is the sum of open loop value (OL) and a result of the accumulative
correction values (CV). The EEV corrections are calculated every EEVCVTConst seconds.
12.5.4 Outdoor Fan Speed Control
12.5.4.1 Speed Definition
The outdoor fans can work in 16 speed states controlled by OMT sensor in cool mode and ICT
sensor in heat mode in ralation to outdoor conditions.
¦
CVOL
EEVEEVEEV
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