Electra WNG 50 DCI Service Manual page 72

CONTROL SYSTEM
12.5.8.3.2 Indoor Coil over Heating Protection
ICT
Decreasing
ICT > 55
53 < ICT ≤ 55
49 < ICT ≤ 53
47 < ICT ≤ 49
45 < ICT ≤ 47
43 < ICT ≤ 45
ICT ≤ 43
12.5.8.4 ODU Protections
There are 3 ODU protections:
•
Compressor overheating
•
Heat sink overheating
•
System over power
Operation logic of all protections is the same. The controlled input (CTT, HST, or PWR) is
controlled by changing the protection level using the fuzzy logic algorithm according the input
level and the change rate.
There are two sets of POWER values, the selection of the values are set according to the state
of the Power-Shed dry contact input.
Power-Shed input open Power1
Power-Shed input short Power2
The following table summarizes the basic levels of each protection.
Protection
level
Stop compressor
Down 2
Down 1
Stop rise
Normal
12.5.8.5 Total Protection Level Definition
The total protection level is defined by the higher level of protection received.
12.5.9 Deicing
12.5.9.1 Deicing Starting Conditions
Deicing operation will start when either one of the following conditions exist:
Case 1: OCT < OAT – DST AND TLD > DI
Case 2: OCT < OAT – 12 AND TLD > 30 minutes.
Case 3: OCT is Invalid AND TLD > DI
Case 4: Unit is just switched to STBY AND OCT < OAT – DST
Case 5: NLOAD = 0 AND OCT < OAT - DST
Case 6: OAT is invalid AND OCT< DST AND TLD > DI AND Compressor ON Time > CTMR
minutes
12-16
Fast
Decreasing
SC SC
D1 D1
SR SR
SR SR
Norm Norm
Norm Norm
Compressor Compressor
Overheat - cool Overheat - heat
(CTT)
105
100
98
95
90
Revision Y05-02
CONTENT
ICT Trend
No Change Increasing
SC SC
D2 D2
D1 D2
SR D1
SR SR
Norm SR
Normal
Heat Sink
(HST)
(CTT)
105 83
100 81
95 77
85 75
80 73
Service Manual - WNG 50_60_80 DCI
Fast
Increasing
SC
D2
D2
D2
D1
SR
Power1 Power2
3600 2900
3400 2750
3200 2600
3100 2450
3050 2300