Electra Delta 25 Service Manual page 35

11.7.5 Heat Sink Over Heating Protection
A new control status will be set according to the following graph every one-minute or whenever when
going up by the rows.
HST is the current reading of HST and HST
n
HST
n
HST > HSTOH5
n
HSTOH4 ≤ HST < HSTOH5
n
HSTOH3 ≤ HST < HSTOH4
n
HSTOH2 ≤ HST < HSTOH3
n
HSTOH1 ≤ HST < HSTOH2
n
HST < HSTOH1
n
(*) Normal (Norm) – No protection status is ON.
Stop-Rise (SR) – System is in protection.
HzDown1 (D1) - System is in protection.
HzDown2 (D2) - System is in protection.
11.7.6 Outdoor Coil Deicing Protection
11.7.6.1 Deicing Starting Conditions
Deicing operation will start when either one of the following conditions exist:
 Case 1: OCT <-DST – AND TLD > DI
 Case 2: OCT < OAT

Case 3: OCT <-1 AND TLD> 100 mnutes.
 Case 4: OCT is Invalid AND TLD > DI
 Case 5: Unit is just switched to STBY AND OCT <-DST
 Case 6: NLOAD = 0 AND OCT <-DST
DST Calculation:
When OATmax >0 or OAT is invalid; then DST=8
When OATmax ≤0; then DST= round down (-0.8 * OATmax) + 8
OATmax calculation:
After compressor starts for 3 minutes, OATmax calculation is start.
The OATmax is the moving value of the Maximum OAT during the 1st 10mintues within last
30minutes
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.
SM DELTAZ 1-E.0 GB
is the last reading of HST.
n-1
<-1 -1
SC SC
D1 D1
SR SR
SR SR
Norm Norm
– 12 AND TLD > 30 minutes.
max
CONTENTS
CONTROL SYSTEM
HST -HST
n n-1
0 1
SC SC
D2 D2
D1 D2
SR D1
Norm SR
Norm
>1
SC
D2
D2
D1
SR
11-7