Troubleshooting
46 RT-SVX25G-EN
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 LEDs 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 Table 16, p. 46.
Programmable & Digital Zone
Sensor Test
Testing Serial Communication Voltage
1. Verify 24 Vac is present between terminals J6-14 and
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 “Start Up,” p. 36”.
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.
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.
Table 16. Default operation for mechanical ZSM (CV
only)
J6 I n p u t / Co n n ect i on
I f n o i n p u t / co n n e c t i on t h i s
h ap p e n s
J6-7
( a)
- Heat indicat ion
( a) t hese connect ions are only on cert ain m odel ZSMs
LED will not com e on while heat ing
LED will not flash during heat fail
J6-8
( a)
- Cool indicat ion
LED will not com e on w hile cooling
LED will not flash during cool fail
( a)
J6-9
( a)
- Sy st em in di cat i on
( sys on)
LED will not com e on while unit has power
J6-10
( a)
- Service
indicat ion
LED will not com e on w hen CFS or FFS
trips
Table 17. System mode and fan selection
Re sist an ce
Va l v es
( K- Oh m s)
Zon e Se n so r
Un i t / Fa n
Mo d e
Loca l Un i t
Mo d e
Lo ca l Fan
Mo d e
2.32 Off/ Auto Off Auto
4.87 Cool/ Aut o Cool Auto
7.68 Aut o/ Auto Auto Aut o
10. 77 Off/ On Off On
13.32 Cool/ On Cool On
16.13 Aut o/ On Auto On
19.48 Heat/ Auto Heat Aut o
27.93 Heat / On Heat On
35.0
Emergency
Heat / Aut o
Emergency
Heat
Auto
43.45
Emergency
Heat / On
Emergency
Heat
On
Out of Range
( Short )
I NVALI D/ Short
I nvalid ( CV) ,
Auto ( VAV)
I nvalid
Out of Range
( Open)
I NVALI D/ Open
I n v a l id ( CV) , Off
( VAV)
I n v a l id
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