Demand Defrost Mode - Carrier PHD4 Series Installation Instruction

PHD4 Series K and WPH4 Series K: Installation Instruction
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.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
HIGH
QC5
KZ
R13 C8 R11
07 09 0L0 08
ALO
C9
C4
QIL Z2 06 04
A7 R9 AB A15
D5 D3
C7
JW5
R3 R5 R6
R2
P2
QCB
Y
R W2 Y
SSTZ-8
P1
W3 W2
Fig. 21 – Interface Fan Board (IFB)
Fig. 22 – Typical Heat Pump Operation, Heating Mode
24
LOW COM
QC4
QC3
KL
DCR QCR
C
Q1
D2
QC1
Q3
AL2
RL
G1
01
G2
C0 F1
Z1
U1
R4 RL4
C3
JWZ
JW3
P4
C W3 W3 W2 W2 C
JW4
Y2 Y1
G C R
DH Y
After the defrost condition is satisfied, or after a maximum of 10 minutes
in defrost mode, the unit will resume normal heating operation.
A09059
C03012