Test 4 - Led Indicator Test; Cool & Service); Relative Humidity Sensor Test; Programmable & Digital Zone Sensor Test - Trane YSC037E Installation & Operation Manual

terminals 2 and 4 on the Zone Sensor.The possible switch
combinations are listed below with their corresponding
resistance values.
Test 4 - LED Indicator Test, (SYS ON, HEAT,
COOL & SERVICE)
Method 1
Testing the LED using a meter with diode test function.Test
both forward and reverse bias. Forward bias should
measure a voltage drop of 1.5 to 2.5 volts, depending on
your meter. Reverse bias will show an Over Load, or open
circuit indication if LED is functional.
Method 2
Testing the LED with an analog Ohmmeter. Connect
Ohmmeter across LED in one direction, then reverse the
leads for the opposite direction.The LED should have at
least 100 times more resistance in reverse direction, as
compared with the forward direction. If high resistance in
both directions, LED is open. If low in both directions, LED
is shorted.
Method 3
To test LED's with ZSM connected to unit, test voltages at
LED terminals on ZSM. A measurement of 32 VDC, across
an unlit LED, means the LED has failed.

Relative Humidity Sensor Test

This component is measured by measuring the mA output
signal on the Relative Humidity Sensor. Verify accuracy of
the sensor annually. If the output reading is 0 mA, first
verify that power is applied to the sensor. A reading of 4
mA corresponds to 0% RH and 20 mA corresponds to 100%
RH.
% RH mA
30 8.8
40 10.4
50 12.0
60 13.6
70 15.2
80 16.8
Note: Measurements should be made from LED common
(ZSM terminal 6 to respective LED terminal).
Programmable & Digital Zone Sensor
Test
Testing serial communication voltage
1. Verify 24 VAC is present between terminals J6-14 & J6-
11.
2. Disconnect wires from J6-11 and J6-12. Measure the
voltage between J6-11 and J6-12, should be about 32
VDC.
RT-SVX21P-EN
3. Reconnect wires to terminals J6-11 and J6-12. Measure
voltage again between J6-11 and J6-12, voltage should
flash high and low every 0.5 seconds.The voltage on
the low end will measure about 19 VDC, while the
voltage on the high end will measure from
approximately 24 to 38 VDC.
4. Verify all modes of operation, by running the unit
through all of the steps in the "Test Modes" section
discussed in "Unit Start-Up" .
5. After verifying proper unit operation, exit the test
mode.Turn the fan on continuously at the ZSM, by
pressing the button with the fan symbol. If the fan
comes on and runs continuously, the ZSM is good. If
you are not able to turn the fan on, the ZSM is
defective.
ReliaTel™ Refrigeration Module (RTRM)
Default Chart
If the RTCI loses input from the building management
system, the RTRM will control in the default mode after
approximately 15 minutes. If the RTRM loses the Heating
and Cooling setpoint input, the RTRM will control in the
default mode instantaneously.The temperature sensing
thermistor in the Zone Sensor Module is the only
component required for the "Default Mode" to operate.

Unit Operation without a Zone Sensor

This procedure is for temporary operation only.The
economizer and condenser fan cycling functions are
disabled.
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote
disconnects before servicing. Follow proper lockout/
tagout procedures to ensure the power can not be
inadvertently energized. Failure to disconnect power
before servicing could result in death or serious injury.
1. Open and Lock the unit disconnect switch.
2. Remove the Outside Air Sensor (OAS) from the
condenser section of unit.
3. Use two (2) wire nuts, to individually cap the wires.
4. Locate the RTRM (J6). Connect two (2) wires to
terminals J6-1 and 2.
5. Connect the sensor (OAS) using two wire nuts to the
two (2) field supplied wires that were connected to
terminals 1 and 2 on J6.
Troubleshooting
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