Trane HUV Installation, Operation And Maintenance Manual page 92

Diagnostics
Table 34. Electric heat not operating (Tracer ZN520)
Probable
Cause Explanation
Normal The controller cycles electric heat on and off to meet the
operation unit capacity requirements.
Requested It is possible to communicate the operating mode (such as
mode: off off, heat, cool) to the controller. When off is communicated
to the controller, the units shuts off the electric heat.
Communicated Numerous communicated requests may disable electric
disable heat, including an auxiliary heat enable input and the heat/
cool mode input. Depending on the state of the
communicated request, the unit may disable electric heat.
Manual output The controller includes a manual output test sequence that
test verifies analog and binary output operation and associated
output wiring. However, based on the current step in the
test sequence, the electric heat may not be on. Refer to
"Manual Output Test (Tracer ZN520)," p.
Diagnostic A specific list of diagnostics affects electric heat operation.
present For more information, see
Unit The controller must be properly configured based on the
configuration actual installed end devices and application. When the unit
configuration does not match the actual end device, the
electric heat may not work properly.
No power to If the controller does not have power, electric heat does not
the controller operate. For the controller to operate normally, a 24 Vac
input voltage must be applied. When the green LED is off
continuously, the controller does not have sufficient power
or has failed.
Unit wiring The wiring between the controller outputs and the electric
heat contacts must be present and correct for normal
electric heat operation. Refer to the typical unit wiring
diagrams.
ECM Motor / ECM controls include sophisticated fan proving / interlock
Control Board circuitry that will disable electric heat if one or more motors
Failure are not performing normally
Hot water is On units with changeover coil and electric heat,
present on a simultaneous operation of hydronic heat and electric heat
changeover is not allowed.
unit
Table 35. Fresh air damper stays open (Tracer ZN520)
Probable
Cause Explanation
Normal The controller opens and closes the fresh air damper based
operation on the controller's occupancy mode and fan status.
Normally, the fresh air damper is open during occupied mode
when the fan is running and closed during unoccupied mode.
Manual output The controller includes a manual output test sequence that
test verifies analog and binary output operation and associated
output wiring. However, based on the current step in the test
sequence, the fresh air damper may not be open. Refer to
"Manual Output Test (Tracer ZN520)," p.
Unit The controller must be properly configured based on the
configuration actual installed end devices and application. When the unit
configuration does not match the actual end device, the
damper may not work correctly.
Unit wiring The wiring between the controller outputs and the fresh air
damper must be present and correct for normal damper
operation. Refer to the typical unit wiring diagrams.
92
90.
"Diagnostics," p. 88.
90.
Table 36. Fresh air damper stays closed (Tracer ZN520)
Probable
Cause Explanation
Normal The controller opens and closes the fresh air damper based
operation on the controller's occupancy mode and fan status.
Normally, the fresh air damper is open during occupied mode
when the fan is running and closed during unoccupied mode.
Warmup and The controller includes both a warmup and cooldown
cooldown sequence to keep the fresh air damper closed during the
transition from unoccupied to occupied. This is an attempt to
bring the space under control as quickly as possible.
Requested It is possible to communicate the operating mode (such as
mode: off off, heat, cool) to the controller. When off is communicated
to the controller, the unit closes the fresh air damper.
Manual output The controller includes a manual output test sequence that
test verifies analog and binary output operation and associated
output wiring. However, based on the current step in the test
sequence, the fresh air damper may not be open. Refer to
"Manual Output Test (Tracer ZN520)," p.
Diagnostic A specific list of diagnostics effects fresh air damper
present operation. For more information, see
Unit The controller must be properly configured based on the
configuration actual installed end devices and application. When the unit
configuration does not match the actual end device, the
damper may not work correctly.
No power to If the controller does not have power, the fresh air damper
the controller does not operate. For the controller to operate normally, a
24 Vac input voltage must be applied. When the green LED
is off continuously, the controller does not have sufficient
power or has failed.
Unit wiring The wiring between the controller outputs and the fresh air
damper must be present and correct for normal damper
operation. Refer to the typical unit wiring diagrams.
90.
"Diagnostics," p. 88.
UV-SVN02C-EN