Diagnostics
108
RT-SVX34F-EN
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
“Test Modes“, p.55
.
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
CV and SZ VAV Units.
If the RTRM 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 from the
potentiometers, the RTRM will control in the default mode
instantaneously. The temperature sensing thermistor in
the Zone Sensor Module for CV applications is the only
component required for the “Default Mode” to operate.
VAV Units.
If the RTRM loses input from the building
management system, the RTRM will control in the default
mode after approximately 15 minutes. For VAV units, a
“shorted” mode input is the only input required for the
“Default Mode” to operate. If the RTRM loses setpoint
inputs from the RTAM due to remote setpoint input failure,
the RTRM will use default setpoint inputs as defined in the
default chart for VAV units.
Economizer Actuator (ECA)
Test Procedures
Verify Economizer Status by Economizer Actuator (ECA)
LED indicator:
OFF: No Power or Failure
ON: Normal, OK to Economize
Slow Flash: Normal, Not OK to Economize
Fast Flash: ¼ Second ON/2 Seconds OFF
Communications Failure
1 Flash: Actuator Fault
2 Flashes: CO2 Sensor out of range
3 Flashes: RA Humidity Sensor out of range
4 Flashes: RA Temp Sensor out of range
6 Flashes: OA Humidity Sensor out of range
7 Flashes: OA Temp Sensor out of range
8 Flashes: MA Temp Sensor out of range
9-11 Flashes: Internal ECA failure
Note:
The Outdoor Air Sensor (OAS) is also used for the
economizer operation. It is connected to the RTRM.
Test 1: Voltage
Disconnect the OAS from the wires in the return air
section. Check the voltage at the wires going to the RTRM.
The voltage should be 5 (± 0.25) Vdc.
Check the resistance at the wires going to the OAS and
measure the temperature at the OAS location. Using the
Temperature versus Resistance chart, verify the accuracy
of the OAS.
If voltage specified is not present, the ECA has failed.
Test 2: Testing the ECA sensors.
1.
Testing the Mixed Air Sensor (MAS). Disconnect the
cable connected to MAT on the ECA. Using the
Thermistor Resistance / Temperature Chart (
Table 16,
p. 35
):
Table 81.
Constant volume and single zone VAV default
operations
Component or
Function Default
Operation
Cooling Setpoint (CSP) 74°F
Heating Setpoint (HSP)
Economizer
71°F Normal Operation
Economizer Minimum
Position
Normal Operation
Mode
Normal operation, or auto if ZSM mode switch
has failed
Fan
Normal operation, or continuous if fan mode
switch on ZSM has failed
Night Setback Mode
Disabled - Used with Integrated Comfort™
System and Programmable ZSM’s only
Supply Air Tempering
Disabled - Used with Integrated Comfort™
Systems only
DA Cool Setpoint
50ºF (SZ VAV Only)
DA Heat Setpoint
100ºF (SZ VAV Only)
Table 82. Variable air volume default operation
Component or Function
Default Operation
Supply Air Cooling Setpoint Failure 55° F
Supply Air Reset Setpoint Failure
Disable Reset
Supply Air Reset Amount
Disable Reset
Supply Air Static
Setpoint Failure
0.5 IWC
Supply Air Static
Deadband Failure
0.5 IWC
Morning Warm-Up
Setpoint Failure
Disable MWU and DWU
Mode Failure “Open
“Unit Mode “Off”
Mode Failure “Shorted
“Unit Mode “Auto”
