Service manual

15-14
CONTROL SYSTEM > GC 24
SM HADDCI 1-A.2 GB
15.4.19 Deicing
15.4.19.1 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
OAT - Outdoor Air Temperature
TLD - Time from Last Deicing
DI - Deicing Interval (Time Interval between Two Deicing) DST - Deicing static threshold (Temperature)
Deicing interval time when compressor is first started in heat mode, is 10 minutes if OCT < -2, and is 40
minutes in other cases.
Deicing interval time is changed (increased/ decreased in 10 minutes steps) as a function of deicing time. If
deicing time is shorter then former deicing time, the deicing interval time will be increased. If deicing time is
longer then former deicing time, the deicing interval time will be decreased.
15.4.19.2 Deicing Starting Conditions
15.4.19.3 1 Level logic
P2 P3 Level
Don't care 1 Normal
Don't care 0 Overflow
COMP
RV
OFAN
EEV
ON
HEAT
COOL
ON
OFF
EEVDeicerOpen
Any
T1 T2
T3 T3
T1
12
0
Threshold
max. 12 minutes
DT
OCT
T1 = T2 = 36 seconds, T3 = 6 seconds
ANY
0
ON
NLOAD
PUMP
OFF
ON
OPER
LED
OFF
Overflow
W
ater Level
Normal
BLINK
NLOAD is
forced to 0
8 min 8 min
Overflow when
unit is ON
Overflow when
unit is OFF
8 min
CONTENTS