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GENERAL
If operational difficulties are encountered, perform
the preliminary checks below before referring to the
troubleshooting charts.
Verify that the unit is receiving
z
electrical supply power
Make sure the fuses in the fused
z
disconnect switches are intact
After completing the preliminary checks described
above, inspect for other obvious problems such as
leaking connections, broken or disconnected wires,
etc. If everything appears to be in order, but the unit
still fails to operate properly, refer to the "DXM2.5
Troubleshooting Process Flowchart" or "Functional
Troubleshooting Chart."
DXM2.5 BOARD
DXM2.5 board troubleshooting in general is best
summarized as verifying inputs and outputs. After
inputs and outputs have been verified, board
operation is confirmed and the problem must be
elsewhere. Below are some general guidelines for
troubleshooting the DXM2.5 control.
FIELD INPUTS
Conventional thermostat inputs are 24VAC from the
thermostat and can be verified using a voltmeter
between C and Y1, Y2, W, O, G. 24VAC will be present at
the terminal (for example, between "Y1" and "C") if the
thermostat is sending an input to the DXM2.5 board.
Proper communications with a thermostat can be
verified using the Fault LED on the DXM2.5. If the
control is NOT in the Test mode and is NOT currently
locked out or in a retry delay, the Fault LED on the
DXM2.5 will flash very slowly (1 second on, 5 seconds
off), if the DXM2.5 is properly communicating with
the thermostat.
w w w. c l i m a t e m a s t e r. c o m
TranquiliTy® 30 (SE) PrEMiEr TWO-STaGE SEriES– iOM
Troubleshooting
SENSOR INPUTS
All sensor inputs are 'paired wires' connecting each
component to the board. Therefore, continuity on
pressure switches, for example can be checked at the
board connector. The thermistor resistance should be
measured with the connector removed so that only
the impedance of the thermistor is measured.
OUTPUTS
The compressor and reversing valve relays are 24VAC
and can be verified using a voltmeter. For units with
EC blower motors, the DXM2.5 controls the motor
using serial communications, and troubleshooting
should be done with a communicating thermostat
or diagnostic tool. The alarm relay can either be
24VAC as shipped or dry contacts for use with DDC
controls by clipping the JW1 jumper. Electric heat
outputs are 24VDC "ground sinking" and require
a voltmeter set for DC to verify operation. The
terminal marked "24VDC" is the 24VDC supply to the
electric heat board; terminal "EH1" is stage 1 electric
heat; terminal "EH2" is stage 2 electric heat. When
electric heat is energized (thermostat is sending a
"W" input to the DXM2.5 controller), there will be
24VDC between terminal "24VDC" and "EH1" (stage
1 electric heat) and/or "EH2" (stage 2 electric heat).
A reading of 0VDC between "24VDC" and "EH1" or
"EH2" will indicate that the DXM2.5 board is NOT
sending an output signal to the electric heat board.
TEST MODE
Test mode can be entered for 20 minutes by
pressing the Test pushbutton. The DXM2.5 board
automatically exits test mode after 20 minutes.
WARNING
HAZARDOUS VOLTAGE! DISCONNECT ALL ELECTRIC POWER INCLUDING
REMOTE DISCONNECTS BEFORE SERVICING.
Failure to disconnect power before servicing can cause severe
personal injury or death.
C r e a t e d : M a r c h 6 , 2 0 2 4
Models:
SE
024-072
PA G E : 5 7
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Table of Contents
Troubleshooting
