T H E S M A R T S O L U T I O N F O R E N E R G Y E F F I C I E N C Y
Vertical Stack
R e v. : 0 4 / 2 4 / 2 0 1 9
47
c l i m a t e m a s t e r. c o m
Swapped LT1/LT2 thermistors: During test mode, the
control monitors to see if the LT1 and LT2 thermistors are
in the appropriate places. If the control is in test mode,
the control will lockout with code 9 after 30 seconds if:
a. The compressor is on in the cooling mode and the
LT1 sensor is colder than the LT2 sensor, or:
b. The compressor is on in the heating mode and the
LT2 sensor is colder than the LT1 sensor.
ESD (DXM2 only): The ESD (Emergency Shut Down)
mode can be enabled from an external common signal
to terminal ESD to shut down the unit. The green status
light will fl ash code 3 when the unit is in ESD mode.
Diagnostic Features -
The LED on the CXM board
advises the technician of the current status of the CXM
control. The LED can display either the current CXM
mode or the last fault in memory if in test mode. If there
is no fault in memory, the LED will fl ash Code 1 (when in
test mode).
CAUTION!
CAUTION!
Do not restart units without inspection and
remedy of faulting condition. Equipment damage may occur.
Figure 26: DXM2 Sensor Placement
17B0008N05
Leaving Air Temp Sensor
(White (2) Wires Connect
to DXM2-T4)
17B0030N06
Leaving Water Temp Sensor
(Yellow (2) Wires Connect
to DXM2-T2)
17B0031N04
Discharge Line Temp Sensor
(Black (2) Wires Connect
to DXM2-T6)
17B0030N05
Entering Water Temp Sensor
(Green (2) Wires Connect
to DXM2-T3)
LT1 Water Coil Protector
(Grey (2) Wires - Harness
to DXM2-LT1)
LT2 Air Coil Protector
(Violet (2) Wires - Harness
to DXM2-LT2)
Notes:
1. Sensors must be positioned on clean
section of copper tube approximately
as shown, clamped securely, and
completely wrapped (except Leaving Air
Sensor - Do Not wrap) with cork tape.
2. All sensors are NTC 10K OHM. To check
calibration use resistance table in DXM2
AOM.
The green status LED and red fault LED on the DXM 2
board advise the technician of the current status of the
DXM 2 control. The status LED will indicate the current
mode that the DXM 2 control is in. The fault LED will
ALWAYS fl ash a code representing the LAST fault in
memory. If there is no fault in memory, the fault LED will
fl ash Code 1. The yellow test LED will turn on when in
test mode.
CXM/DXM 2 Control Start-up Operation -
The control
will not operate until all inputs and safety controls are
checked for normal conditions. The compressor will have
a 5 minute anti-short cycle delay at power-up. The fi rst
time after power-up that there is a call for compressor,
the compressor will follow a 5 to 80 second random start
delay. After the random start delay and anti-short cycle
delay, the compressor relay will be energized. On all
subsequent compressor calls, the random start delay is
omitted.
DXM2 has 4 sensors that can be read with service tool
ACDU03C and harness 11B0100N27 or thermostat
ATC32U03C. Sensors are entering and leaving water
temperature, leaving air temperature, and discharge line
temperature. (See FIG 26)
