Service manual

CONTROL SYSTEM
11.5.7.3.2 Indoor Coil over Heating Protection
ICT
ICT Trend
Fast
Dec
reasing
Decreasing No Change Increasing
Fast
Increasing
ICT > 55 SC SC SC SC SC
53 < IC
T ≤ 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
11.5.7.4 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
Æ Power1
Power-Shed input sort
Æ Power2
The following table summarizes the basic levels of each protection.
Protection
level
Compressor
O
verheat - cool
(CTT)
Compressor
Overheat - heat
(CTT)
Heat Sink
(HST)
Power1
Power2
Stop compressor
105 105 83 3600 2900
Down 2
100 100 81 3400 2750
Down 1
98 95 77 3200 2600
Stop rise
95 85 75 3100 2450
Normal
90 80 73 3050 2300
11.5.7.5 Total Protection Level Definition
The total protection level is defined by the higher level of protection received.
11.5.8 Deicing
11.5.8.1 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
OCT – Outdoor Coil Temperature
11-16
Revision 0