Electra WNG 50 DCI Service Manual page 46

Outdoor Coil Deicing Protection
11.19.6
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.
Deicing Protection Procedure
11.19.7
OCT
12
0
Threshold
ON
COMP
HEAT
RV
COOL
ON
OFAN
OFF
EEVDeicerOpen
EEV
Any
T1 = T2 = 36 seconds, T3 = 6 seconds
Service Manual - WNG 50_60_80 DCI
T1
max. 12 minutes
DT
T3
Revision Y05-02
CONTENT
T2
T3
CONTROL SYSTEM
T1
11-9