Page 14
24V terminal
strip connections
diagnostic LEDs
pressure
switch
circuit
connections
defrost board
test pins
Component Locations Will
Vary With Board Manufacture
r
ambient
sensor
coil
sensor
field select
temperature pins
Y2
Y2
FIGURE 20
DELA
Y
reversing valve
connections
FIGURE 21
COIL SENSOR LOCATION
HPXA19−036/−048/−060
Coil sensor should be on
the 5th hairpin from the
bottom on the outside loop.
HPXA19−038
Coil sensor should be on
the 8th hairpin down from
the top on the outside loop.
HPXA19−024
Coil sensor should be on the
6th hairpin from the
top
on
the outside loop.
The temperature probes cannot be removed from the con-
trol. The control and the attached probes MUST be re-
placed as a unit. Do not attempt to cut or splice probe wires.
Diagnostic LEDs
The defrost board uses two LEDs for diagnostics. The
LEDs flash a specific sequence according to the diagnos-
tic condition. See table 6.
HI−PS/LO−PS Terminals
High pressure switch (S4) is factory wired into the defrost
board HI−PS terminals. When (S4) trips, the defrost board
will cycle off the compressor and the strike counter in the
board will count one strike.
Low pressure switch (S87) is factory wired into the defrost
board LO−PS terminals. When (S87) trips, the defrost
board will cycle off the compressor and the strike counter
in the board will count one strike.
(S87) is ignored during certain conditions:
During the defrost cycle and 90 seconds after the
termination of defrost
When the average ambient sensor temperature is
below 15 F (−9)
For 90 seconds following the start up of the
compressor
During "Test" mode
5−Strike Lockout Feature
The internal control logic of the board counts the pres-
sure switch trips only while the Y1 (Input) line is active. If
a pressure switch opens and closes four times during a
Y1 (Input), the control logic will reset the pressure switch
trip counter to zero at the end of the Y1 (Input). If the
pressure switch opens for a fifth time during the current
Y1 (Input), the control will enter a lockout condition.
The 5−strike pressure switch lockout condition can be
reset by cycling OFF the 24−volt power to the control
board or by shorting the TEST pins. All timer functions
(run times) will also be reset.
If a pressure switch or discharge line thermostat switch
opens while the Y1 Out line is engaged, a 5−minute short
cycle will occur after the switch closes.
DELAY" Option
The defrost board has a field selectable function to reduce
occasional noise that may occur while the unit is cycling in
and out of defrost mode. When a jumper is installed on the
DELAY" pins, the compressor will cycle off for 30 seconds
going in and out of defrost mode.
NOTE − 30 second off cycle is not functional when
jumpering TEST" pins.
