Installation and Maintenance Manual

VAV-SVX07A-EN 79
Troubleshooting
VAV Damper Failure Troubleshooting Procedures
WARNING
Hazardous Service Procedures!
The maintenance and troubleshooting procedures recommended in this section of the manual
could result in exposure to electrical, mechanical or other potential safety hazards. Always refer
to the safety warnings provided throughout this manual concerning these procedures. When
possible, disconnect all electrical power including remote disconnect and discharge all energy
storing devices such as capacitors before servicing. Follow proper lockout/tagout procedures to
ensure the power can not be inadvertently energized. When necessary to work with live
electrical components, have a qualified licensed electrician or other individual who has been
trained in handling live electrical components perform these tasks. Failure to follow all of the
recommended safety warnings provided, could result in death or serious injury.
In the event that the air valve is not modulating, properly inspect the following:
1. Tracer™ SC or Tracer TU service tool has enabled an override function in the Tracer UC400
controller.
• The overrides are Open, Closed, Min, or Max. Disable all overrides.
Note: See programming and operation chapter to be able to release override with Tracer TU
service tool.
• The Tracer UC400 controller is going through a recalibrate (reset) command. This is shown
in the diagnostic list in Tracer TU service tool.
• Wait for calibration to finish.
2. Zone temperature is greater than the heat setpoint or less than the cool setpoint.
• Change the heat and/or cool setpoint.
3. Actuator not driving full drive time.
• Drive time in advanced configuration not set at 90 seconds on current Varitrane units.
• Adjust to correct damper travel time using Tracer TU service tool. See the Tracer UC400
Operation section.
• Damper actuator loose on shaft.
• Tighten damper actuator set screw to damper shaft.
• Measure the power input to XFMR 24 VAC input and on the Tracer UC400 controller. The
supply voltage should be between 20 and 28 VAC (24 VAC cataloged). However, voltages at
either extreme may result in system instability and cause damper to not be driven its full
range.
• If no voltage, check up stream of controller to see were voltage has been interrupted. See
Figure 37, p. 86 to Figure 44, p. 93 for correct unit diagrams.
4. Actuator motor has failed.
• Check voltage at B on TRIAC outputs to Common , you should have 24 VAC. If 24 VAC is
not present check incoming power to the Tracer UC400 controller on XFMR 24 VAC input and
. Voltage should measure 24 VAC ± 10%. If you measure the proper voltage at XFMR 24
VAC input and and no voltage at B and Common , replace the Tracer UC400 controller.
• Check motor by applying 24 VAC directly to common (blue) and jumper open (black) wire to
a ground to drive damper open.
• Damper should drive open.
• Check motor by applying 24 VAC directly to common (blue) and jumper closed (red) wire to
a ground to drive damper closed.