7
DXM2.5 Unit Control
Created: October 18, 2022
THE SMART SOLUTION FOR ENERGY EFFICIENCY
FIELD SELECTABLE INPUTS
Test Mode: Test mode allows the service technician to
check the operation of the control in a timely manner.
By momentarily pressing the TEST pushbutton, the
DXM2.5 control enters a 20 minute test mode period
in which all time delays are sped up 15 times. Upon
entering test mode, the Status and Fault LED displays
will change. The Status LED will either ash rapidly
to indicate the control is in the test mode, or display a
numeric ash code representing the current airow if an
ECM blower is connected and operating. The Fault LED
will display the most recent fault condition in memory.
NOTE: A ash code of 1 indicates there have been no
faults stored in memory.
For diagnostic ease at conventional thermostats, the alarm
relay will also cycle during test mode. The alarm relay will
cycle on and off in sync with Fault LED to indicate a code
representing the last fault, at the thermostat.
The test mode can be exited by pressing the TEST
pushbutton for 3 seconds. The test mode can also be
entered and exited by cycling the G input, 3 times within
60 seconds.
During test mode, the control monitors to see if the
LT1 and LT2 thermistors are connected and operating
properly. If the control is in test mode, the control will
lockout, with Code 9, after 60 seconds if:
a) The compressor is On in Cooling Mode and the LT1
sensor is colder than the LT2 sensor. Or,
b) The compressor is On in Heating Mode and the LT2
sensor is colder than the LT1 sensor.
Retry Mode: If the control is attempting a retry of a fault,
the Fault LED will slow ash (slow ash = one ash
every 2 seconds) to indicate the control is in the process
of retrying.
Field Conguration Options: NOTE: In the following eld
conguration options, jumper wires should be clipped
ONLY when power is removed from the DXM2.5 control.
NOTE: Jumper 3 must not be clipped prior to adding
antifreeze to the water loop. Antifreeze protection to
10°F required. Clipping JW3 without antifreeze may
result in freeze damage and will void the unit warranty.
Water Coil Low Temperature Limit Setting: Jumper
3 (JW3-LT1 Low Temp) provides eld selection of
temperature limit setting for LT1 of 30°F or 10°F [-1°F or
-12°C] (refrigerant temperature).
Not Clipped = 30°F. Clipped = 10°F.
DXM2.5 Controls
Alarm Relay Setting: Jumper 1 (JW1-AL2 Dry) provides
eld selection of alarm function when Alarm Relay is
energized.
Not Clipped = AL1 connected to R (24VAC) with Alarm
Relay active.
Clipped = Dry contact connection between AL1 and AL2
with Alarm Relay active.
JUMPERS (Set at Factory)
A0-2: Congure Modulating Valve or Variable-Speed
Pump (vFlow®Models Only)
Set A0-2 jumper (see Figure on page 5) to “0 - 10v” if
using Internal Modulating Motorized Valve or “PWM” if
using Internal Variable-Speed Pump. This applies only to
vFlow®units with Internal Speed Water Flow Control.
DIP SWITCHES
NOTE: In the following eld conguration options,
DIP switches should only be moved when power is
removed from the DXM2.5 Control to ensure proper
operation.
DIP Package #1 (S1): DIP Package #1 is 8 position
and provides the following setup selections.
DIP 1.1 – Unit Performance Sentinel Disable: Provides
eld selection to disable the UPS feature.
On = Enabled. Off = Disabled.
DIP 1.2 – Compressor Relay Staging Operation:
Provides selection of Compressor Relay staging operation.
The Compressor Relay can be selected to turn on with
Stage 1 or Stage 2 call from the thermostat. This is used
with Dual Stage units (2 compressors where 2 DXM2.5
Controls are being used) or with master/slave applications.
In master/slave applications, each compressor and fan will
stage according to its appropriate DIP 1.2. If set to stage
2, the compressor will have a 3 second on-delay before
energizing during a Stage 2 demand. Also, if set for stage
2, the Alarm Relay will NOT cycle during test mode.
On = Stage 1. Off = Stage 2.
DIP 1.3 – Thermostat Type (Heat/Cool): Provides
selection of thermostat type. Heat Pump or Heat/Cool
thermostats can be selected. When in Heat/Cool Mode,
Y1 is input call for Cooling Stage 1, Y2 is input call for
Cooling Stage 2, W1 is input call for Heating Stage 1,
and O/W2 is input call for Heating Stage 2. In Heat Pump
Mode, Y1 is input call for Compressor Stage 1, Y2 is input
call for Compressor Stage 2, W1 is input call for Heating
