56 RT-SVX23D-EN
Trouble Shooting
Cool SP = Terminals 2 and 3
Range = 100 to 900 Ohms approximate
Heat SP = Terminals 2 and 5
Range = 100 to 900 Ohms approximate
Test 3 System Mode and Fan Selection
The combined resistance of the Mode selection switch and the Fan selection switch can be
measured between 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.
Note: Measurements should be made from LED common (ZSM terminal 6 to respective LED
terminal). Refer to the Zone Sensor Module (ZSM) Terminal Identification table at the
beginning of this section.
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.
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.
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