9
NOTE: If the TEST pins are jumpered and the 5-minute delay is
being bypassed, the LO PS terminal signal is not ignored during
the 90-second start-up period.
NOTES:
■
Because the pressure switches are monitored only when “Y1”
(Input) is active, the code for pressure switch open will not be
seen when “Y1” is off. Instead, the “Normal Operation” or
“Short Cycle Lockout” code will be seen.
■
When a pressure switch opens and causes a short cycle
lockout, the pressure switch-open code will be seen until it
closes, then the short cycle lockout code will flash unless it
has already expired.
Adjust Defrost System
Defrost Control Board
Optional high pressure switch connections
NOTE: To add the pressure switch, remove the factory-installed
jumper.
Adjust Time Between Defrost Cycles
1. Disconnect power.
2. Remove the heater compartment access panel.
3. Adjust the time period between defrost cycles by placing the
defrost time plug in the proper position. See “Defrost Control
Board.”
■
For 30-minute intervals between defrost cycles, connect
the Defrost Time Setting Plug to the pins corresponding
to 30.
■
For 60-minute intervals between defrost cycles, connect
the Defrost Time Setting Plug to the pins corresponding
to 60 (this setting is the factory preset setting).
■
For 90-minute intervals between defrost cycles, connect
the Defrost Time Setting Plug to the pins corresponding
to 90.
4. Replace the heater compartment access panel.
5. Reconnect power.
Troubleshoot the Defrost System
Diagnostic LEDs
The defrost board uses 2 LEDs for diagnostics. The LEDs flash a
specific sequence according to the condition.
Defrost Control Board Diagnostic LEDs
Mode
Green LED
(DS2)
Red LED
(DS1)
No Power to Board
Off
Off
Normal Operation/Power to Board
Simultaneous Slow Flash
Short Cycle Lockout
Alternating Slow Flash
Low Pressure Switch Fault
Off
Slow Flash
Low Pressure Switch Lockout
Off
On
High Pressure Switch Fault
Slow Flash
Off
High Pressure Switch Lockout
On
Off
A. Defrost time setting pins
B. Test pins
C. Compressor delay pins
D. Reversing valve
E. Low pressure switch (optional)
F. Defrost thermostat
G. High pressure switch (optional)
H. Diagnostic LEDs
I. Low voltage terminal strip
connections
K1 Relay
K2 Relay
FAN
DS1
L
24V
P2
P5
O-OUT
DF
Y1-OUT
HI-PS
U1
U2
DS2
K3 Relay
P6
TST PS DF C
R
O Y1
C5
LO-PS
C2
P1
30
60
90
TEST
W1
C
L
R
Y1
O
H
I
A
B
C
D
E
F
G
Defrost Control Board Diagnostic LED
Mode
Green LED
(DS2)
Red LED
(DS1)
No Power to Board
Off
Off
Normal Operation/Power to Board
Simultaneous Slow Flash
Short Cycle Lockout
Alternating Slow Flash
Low Pressure Switch Fault
Off
Slow Flash
Low Pressure Switch Lockout
Off
On
High Pressure Switch Fault
Slow Flash
Off
High Pressure Switch Lockout
On
Off
WARNING
Electrical Shock Hazard
Disconnect power before servicing.
Replace all parts and panels before operating.
Failure to do so can result in death or electrical shock.
