Comfort Alert Diagnostic Module - Carrier Gemini 38AU07 Series Installation Instructions Manual

if necessary. Service tools are available from RCD that allow
the replacement of the check valve core without having to re-
cover the entire system refrigerant charge. Apply compressor
refrigerant oil to the check valve core's bottom o-ring. Install
the fitting body with 96 ±10 in.-lbs (1085 ±23 N-cm) of torque;
do not overtighten.
SEAT
.47
5/8" HEX
CORE
(Part No. EC39EZ067)
WASHER
O-RING
1/2" HEX
This surface provides a metal to metal seal when
torqued into the seat. Appropriate handling is
required to not scratch or dent the surface.
Fig. 39 — CoreMax
HOT GAS BYPASS VALVE ADJUSTMENTS
Refer to Fig. 33 for a unit piping schematic with factory
option Hot Gas Bypass control.
The suction pressure regulating valve is located between the
unit's compressor discharge line and the desuperheating tank.
A suction pressure tube is connected between the regulating
valves and the unit suction line. This valve is factory set to be-
gin to open as suction pressure drops below 109 psig (752
kPa). This valve can be adjusted by removing the cover bolt on
the valve to expose the Allen key socket. One turn of this stem
provides a 5 psig (34 kPa) change in valve opening setting. CW
turn reduces the opening setting. CCW turn increases the open-
ing setting. MAXIMUM CCW adjustment is one turn.
The factory setting is designed to provide a longer run time
during first stage cooling operation by beginning to open at ap-
proximately 36°F (2°C) evaporator saturated suction tempera-
ture as space load approaches satisfaction. This extended run
time will provide additional dehumidification effect.

Comfort Alert Diagnostic Module

The Comfort Alert Diagnostic Module (CADM) monitors
and analyzes data from the Copeland Scroll three-phase com-
pressor and the thermostat demand. The CADM also provides
a 3-minute anti-recycle time delay to compressor cycling.
Each compressor has a separate CADM module.
The CADM detects causes for electrical and system relat-
ed failures without any sensors. Flashing LEDs communicate
the Alert codes to guide service technicians in accurately and
quickly troubleshooting the system and determining root
cause for the failure.
Inputs to the CADM include 24-vac power, thermostat Y1
or Y2, compressor contactor coil (common side) and compres-
sor power leads (from the compressor contactor). See Table 18.
1. CoreMax is a registered trademark of Fastest, Inc.
1/2-20 UNF RH
0.596
30°
45°
DEPRESSOR PER ARI 720
+.01/-.035
FROM FACE OF BODY
7/16-20 UNF RH
1 Access Port Assembly
Table 18 — Comfort Alert Diagnostic Module Inputs
INPUT
Control Power
Demand*
Control Common
Cooling
Contractor Coil
Line A
Line B
Line C
* Only applies to 38AUZ(D,E).
Control of the compressor contactor coil is through a nor-
mally-closed (power on the module) contact between termi-
nals P and C.
Communications of status and alert conditions is through
three LEDs located on the top edge of the module housing (see
Fig. 35): POWER (green), ALERT (yellow), and TRIP (red).
The POWER LED indicates the presence of control power
to the CADM.
The ALERT LED indicates an abnormal condition exists
in the system through a flash code. The ALERT LED will
blink a number of times consecutively, pause and the repeat
the process. The number of blinks, defined in Table 13, cor-
relates to a particular abnormal condition; troubleshooting
tips are provided for each Alert code. Reset of the ALERT
may be automatic or manual. If the fault condition causing
the Alert is self-corrected, the Alert code will be removed and
the CADM will automatically reset and allow the system to
restart normally. Manual reset requires that main power to the
38AU unit be recycled after the cause for the Alert condition
has been detected and corrected.
POWER
(GRN)
POWER
ALERT
(YEL)
ALERT
TRIP
TRIP
(RED)
Fig. 40 — CADM Housing/LED Locations
The TRIP LED indicates either a time-delay period is cur-
rently active (RED LED is blinking) or the module has
locked out the compressor (RED LED is on steady). A lock-
out condition will occur when the CADM detects a thermo-
stat demand at input Y but there is no power at the compres-
sor line terminals T1 or T2 or T3. This lockout can occur due
to a safety switch (LPS or HPS) opening and de-energizing
the compressor contactor, the compressor-motor internal
overload opens, or other internal power interruption has oc-
curred. Reset of the TRIP LED requires that unit main power
be recycled after the loss of power to the compressor condi-
tion has been detected and corrected.
Simultaneous blinking of YELLOW and RED LEDs indi-
cates control power input to the CADM is low. Check control
circuit transformer and wiring.
36
TERMINAL VOLTAGE
R 24-v
Y2 24-v
C 24-v
Y 24-v
P 24-v
T1 Line
T2 Line
T3 Line
Comfort Alert
™
Commercial Diagnostics
Green LED - 24VAC Power
Yellow LED - Flash Code
2 System Pressure Trip
3 Short Cycling
4 Locked Rotor
5 Open Circuit
T1
6 Missing Phase
7 Reverse Phase
8 Welded Contactor
9 Low Voltage
Red LED - Protector Open
or no compressor power
Active Protection T2
PROT breaks 24VAC common
leg of compressor contactor coil
Reset codes and PROT lockout
by removing 24VAC to module
For Two-Stage Applications:
T3
DC SOL operating range: 4-18VAC
Compressor second stage is
energized when YA & Y2 are 24VAC
and Alert and Trip LEDs are off
EMERSON ™
Climate Technologies