Service manual

CONTROL SYSTEM
11.5.2.5 Speed Step Limitations
11.5.2.5.1 Step 1 and step 2
The compressor speed cannot go below Step1RPS or abo
ve Step2RPS during 3 continuous
minutes once after the compressor starts up when the ODU unit changes from STBY
11.5.2.5.2 Step 3 limit
The speed cannot go higher than Step3RPS unless it was op
erating for more than 1
continuous minute between Step3RPS – 5 and Step3RPS.
11.5.3 EEV Control
11.5.3.1 Operation Range
The EEV operation range is defined according to the operation mode as following
ODU Mode Normal operation IDU inactive Compressor off
SB
200
200
COOL 80 to 350 0
HEAT 70 to 400 60 to 140
11.5.3.2 Reaching target value rules
For all cases except at EEV initialization procedure, each EEV can move no more than 20
steps at a time.
When required the EEV’s move, one by one in sequence, till the target position is achieved for
every EEV.
The following diagram presents the EEV steps till the target position is set.
EEV3EEV1 EEV2 EEV3 EEV4 EEV1 EEV3 EEV4 EEV4 EEV3 EEV3
EEV2 EEV1 EEV4 EEV3
set set set set
11.5.3.3 EEV Operation when ODU changes to SB Mode
When the ODU mode is changed to SB, the following is performed immediately:
- All EEV’s are set to 200.
- They remain in this position for 60
Sec.
- Then, performs reset (ho
ming) procedure.
11-12
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