PHD4 Series K and WPH4 Series K: Installation Instruction
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
24
A09059
Fig. 21 – Interface Fan Board (IFB)
C03012
Fig. 22 – Typical Heat Pump Operation, Heating Mode
Step 3 – Defrost Control
Demand Defrost Mode
The defrost mode is factory set to an initial 60-minute time interval. It
may also be adjusted to an initial interval of 30, 90, or 120 minutes.
During operation, the control optimizes current defrost time based on the
previous defrost interval and previous defrost period. If the previous
defrost period is less than 2 minutes for two consecutive defrost cycles
the control will lengthen the defrost interval by 15 minutes, up to a
maximum of 120 minutes or 30 minutes greater than the original
setpoint, whichever comes first. If the previous defrost period is more
than 5 minutes for two consecutive defrost cycles the control will
shorten the defrost interval by 15 minutes, down to a minimum of 30
minutes or 30 minutes from the original setpoint, whichever is first.
After the defrost condition is satisfied, or after a maximum of 10 minutes
in defrost mode, the unit will resume normal heating operation.
HIGH
LOW
COM
QC5
QC4
QC3
KZ
KL
07
09
08
0L0
ALO
R13 C8
R11
Q1
Q3
D2
AL2
DCR
QCR
QC1
C
RL
01
G1
G2
Z1
A7
R9
AB A15
C4
C9
C0
QIL
Z2
06
04
U1
C3
R4
RL4
JWZ
C7
D5
D3
R3 R5
R6
R2
JW5
QCB
Y
R
W2 Y
C
W3 W3 W2 W2 C
JW4
P2
JW3
P4
P1
W2
W3
Y2
Y1
Y
DH
G
C
R
SSTZ-8
P3
SDL
24V
AC/R
3AMP
CDM/C
F1
STD
DEHUM
