45
c l i m a t e m a s t e r. c o m
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
Tr a n q u i l i t y
®
2 2 ( T Y ) S e r i e s
R e v. : 1 2 / 1 7 / 1 4
General
If operational diffi culties are encountered, perform
the preliminary checks below before referring to the
troubleshooting charts.
• Verify that the unit is receiving electrical supply power.
• Make sure the fuses in the fused 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 Troubleshooting
Process Flowchart” or “Functional Troubleshooting
Chart.”
DXM2 Board
DXM2 board troubleshooting in general is best
summarized as verifying inputs and outputs. After inputs
and outputs have been verifi ed, board operation is
confi rmed and the problem must be elsewhere. Below
are some general guidelines for troubleshooting the
DXM2 control.
Field Inputs
Conventional thermostat inputs are 24VAC from the
thermostat and can be verifi ed 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 board.
Proper communications with a thermostat can be verifi ed
using the Fault LED on the DXM2. 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 will fl ash
very slowly (1 second on, 5 seconds off), if the DXM2 is
properly communicating with the thermostat.
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. If desired, this
reading can be compared to the thermistor resistance
chart shown in Table 8. An ice bath can be used to check
the calibration of the thermistor.
Outputs
The compressor and reversing valve relays are 24VAC
and can be verifi ed using a voltmeter. For units with
ECM blower motors, the DXM2 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 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 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 board will automatically exit
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.
Troubleshooting
WARNING!
