Nordyne JS4BD-KA Series User's Information And Installation Instructions Manual page 7

Low-Pressure Switch —(Select Models) A low-
pressure switch is factory-installed and located
in the suction line internal to the outdoor unit.
The switch is designed to protect the compressor
from a loss of charge. Under normal conditions,
the switch is closed. If the suction pressure falls
below 5 psig, then the switch will open and de-
energize the outdoor unit. The switch will close
again once the suction pressure increases above
20 psig. Please note that the switch interrupts
the thermostat inputs to the unit. Thus when the
switch opens and then closes, there will be a 5
minute short cycling delay before the outdoor
unit will energize.
High-Pressure Switch—A High-pressure switch
is factory-installed and located in the compressor
discharge line internal to the outdoor unit. The
switch is designed to de-energize the system
when very high pressures occur during abnormal
conditions. Under normal conditions, the switch
is closed. If the discharge pressure rises above
575 psig, then the switch will open and de-ener-
gize the outdoor unit. The switch will close again
once the discharge pressure decreases to 460
psig. Please note that the switch interrupts the
thermostat inputs to the unit. Thus, when the
switch opens and then closes, there will be a 5
minute short cycling delay before the outdoor
unit will energize.
Comfort Alert TM Diagnostics (Select Models)
— The Comfort Alert TM
facilitates troubleshooting heat pump and air
conditioning system failures. This Comfort
Alert TM module is designed only for single-phase
systems with scroll compressors that have
internal overload protection. By monitoring and
analyzing data from the compressor and the
thermostat demand, the module can detect the
cause of electrical and system related failures
without any sensors. A fl ashing LED indicator
communicates the ALERT code and guides the
service technician more quickly and accurately
to the root cause of a problem.
NOTE: This module does not provide safety
protection! The Comfort Alert
monitoring device and cannot control or shut
down other devices.
LED Description (See Figure 2)
POWER LED (Green): indicates voltage is present
at the power connection of the module.
diagnostics module
TM
module is a
ALERT LED (Yellow): communicates an
abnormal system condition through a unique
fl ash code. The ALERT LED will fl ash a number
of times consecutively, pause and then repeat
the process. The number of consecutive
fl ashes, defi ned as the Flash Code, correlates
to a particular abnormal condition. Detailed
descriptions of specifi c ALERT Flash Codes are
shown in Table 1 of this manual.
TRIP LED (Red): indicates there is a demand
signal from the thermostat but no current to the
compressor is detected by the module. The TRIP
LED typically indicates the compressor protector
is open or may indicate missing supply power
to the compressor.
The scroll compressor's run (R), common (C)
and start (S) wires are routed through the holes
in the Comfort Alert TM module marked "R," "C"
and "S."
24 VAC Power Wiring — The Comfort Alert
module requires a constant nominal 24 VAC
power supply. The wiring to the module's R and
C terminals must be directly from the indoor unit
or thermostat.
TM
The Comfort Alert module requires a thermostat
demand signal to operate properly.
NOTE: After the thermostat demand signal is
connected, verify that 24 VAC across Y and C
when demand is present.
TROUBLESHOOTING
Interpreting The Diagnostic LEDs – When
an abnormal system condition occurs, the
Comfort Alert TM module displays the appropriate
ALERT and/or TRIP LED will fl ash a number of
times consecutively, pause and then repeat the
process. To identify a Flash Code number, count
the number of consecutive fl ashes.
Every time the module powers up, the last
ALERT Flash Code that occurred prior to shut
down is displayed for one minute. The module
will continue to display the LED until the condition
returns to normal or if 24 VAC power is removed
from the module.
Cooling — Gradually lower the thermostat
temperature setpoint below the actual room
temperature and observe that the outdoor unit
and indoor blower energize. Feel the air being
TM
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