11-9
CONTROL SYSTEM
SM BS DCI 1- A.1 GB
11.19.6
Outdoor Coil Deicing Protection
Deicing Starting Conditions:
Deicing operation will start when either one of the following conditions exist:
x
Case 1: OCT < OAT – 8 AND TLD > DI
x
Case 2: OCT < OAT – 12 AND TLD > 30 minutes.
x
Case 3: OCT is Invalid AND TLD > DI
x
Case 4: Unit is just switched to STBY AND OCT < OAT – 8
x
Case 5: NLOAD = 0 AND OCT < OAT -8
OCT – Outdoor Coil Temperature
OAT – Outdoor Air Temperature
TLD – Time from Last Deicing
DI – Deicing Interval (Time Interval between Two Deicing)
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.
11.19.7
Deicing Protection Procedure
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
CONTENTS
