Trane VUV Installation, Operation And Maintenance Manual page 104

Diagnostics and Troubleshooting
Red Service LED The red LED normally indicates if the unit
controller is operating properly or not. Refer to
p. 104.
Table 49. Red service LED activity for Tracer® ZN520
controllers
LED Activity
Off continuously after power is applied
to the controller.
On continuously, even when power is
first applied to the controller.
LED flashes about once every second.
Black Service push button.
Note: If the service push button is held down for more than
15 seconds, the Tracer® controller will uninstall itself
from the ICS communication network and shutdown all
unit operation. This mode is indicated by the red
Service LED flashing once every second. See the Red
Service LED section. Use the Rover service tool to
restore the unit to normal operation. Refer to the
service tool product literature for more information
Figure 89. LED light status on ZN520 controller
Green STATUS LED
Indicates whether the
controller is powered on
(24 Vac supplied)
Yellow COMM LED
Indicates if communication is
functioning
Red SERVICE LED
Indicates if service is needed
Manual Output Test
The purpose of the manual output test sequence for Tracer®
ZN520 controllers is to verify output and end device operation.
Use the manual output test to:
• Verify output wiring and operation without using Rover,
service tool
Table 50. Test sequence for 1-heat/1-cool configurations for Tracer® ZN520
Steps
1. Off
2. Fan High
3. Fan Medium
4. Fan Low
5. Cool
6. Heat
7. Fresh Air Damper
8. Exit
(a) For all 1-heat/1-cool applications including 2-pipe changeover, BOP4 energizes in the cooling test stage and BOP5 energizes in the heat test stage.This occurs even though
during normal 2-pipe changeover operation BOP4 controls the unit valve for both cooling and heating.
(b) At the beginning of the Fan High step, the controller attempts to clear all diagnostics.
(c) The fresh air damper (BOP6) only energizes during this step if binary output 6 has been configured as a fresh air damper.
(d) After the Fresh Air Damper step, the test sequence performs the Exit step.This initiates a reset and attempts to return the controller to normal operation.
104
Table 49,
Description
Normal operation
Someone is pressing the Service button
or the controller has failed.
Uninstall (normal controller mode). To
restore normal operation, use the Rover
service tool.
Use the Service button to install the
Tracer® ZN520 controller in a
communication network.
2
3
Fan BOP1-3 Cool Output BOP4
Off
High
Medium
Low
High
High
High
(d)
• Force the water valve to open and balance the hydronic
system
Note: The manual output test is not an automatic cycle. You
must press the TEST button to proceed through each
step.
The controller observes all diagnostics that occur during the
test sequence. Although an automatic diagnostic reset
sequence exists as part of the controller's normal operation,
the automatic diagnostic reset feature is not active during the
test sequence.
If left in an individual test step, the controller remains in test
mode for 60 minutes and then exits to normal operation.
Many service calls are due to unit diagnostics. The test
sequence resets unit diagnostics and attempts to restore
normal unit operation prior to testing the outputs. If the
diagnostics remain after a reset, the STATUS LED indicates
the diagnostic condition is still present (two blinks).
Manual Output Test Procedure
Follow the procedure below to test Tracer® ZN520 controllers.
1. Press and hold the TEST button for at least two seconds
(not exceeding 5 seconds), and then release, to start the
test mode.
2. The test sequence will turn off all outputs and then attempt
to clear all diagnostics.
1
3. Press the TEST button several more times (no more than
once per second) to advance through the test sequence.
The outputs are not subject to minimum times during the test
sequence. However, the test sequence only permits one step
per second which limits minimum output time.
The green LED is turned off when the TEST button is pressed.
To begin the manual output test mode, press and hold the
TEST button (turning off the green LED) for at least two
seconds.The green LED will begin to blink, indicating the
controller is in test mode. See
(a)
Heat Output BOP5
Off
(b)
Off
Off
Off
On
Off
Off
Table 50, p. 104.
Damper BOP6
Off Closed
Off Closed
Off Closed
Off Closed
Off Closed
On Closed
Off Open
UV-SVX005G-EN
(c)