Trane Tracer UC400 - Wired Zone Sensor Setpoint Failure

64 VAV-SVX07F-EN
Troubleshooting
• Turn motor speed control potentiometer slowly, fully clockwise. The motor should smoothly
ramp to full speed.
• If the PSC motor speed controller fails, replace it.
VAV Electric Heat Stage Failure
WARNING
Live Electrical Components!
During installation, testing, servicing and troubleshooting of this product, it may be necessary
to work with live electrical components. Have a qualified licensed electrician or other
individual who has been properly trained in handling live electrical components perform these
tasks. Failure to follow all electrical safety precautions when exposed to live electrical
components could result in death or serious injury.
In the event that the heat
outp
uts do not energize, check the following:
• Zone temperature is at or above the heating setpoint. Increase the UC400 controller heating
setpoint.
• V
erify the output configuration in the UC400
controller setup screen. Unit needs to be
configured as 3-stage electric heat.
• Tracer SC has the electric heat output
disabled. Check group, global, and/or Tracer overrides to
make sure they are not inhibiting heat operation.
• Minimum heating CFM is not being met, airflow is too low. Increase the airflow or lower the
mi
nimum he
ating flow.
• Heat relays have failed.
– If the UC400 controller is calling for electric heat
(viewed in the Status scree
n), then the LED
is ON for correct binary output(s) for the stage(s) of heat to be ON. If not, then check the
UC400 controller TRIAC output, wiring connections, and relay output.
– Check correct binary output to common
. It should have 24 Vac. If it does not, measure
the power input to on XFMR 24 Vac input and of the UC400 controller. The supply voltage
should be between 20.4 and 27.6 Vac (24 Vac cataloged). However, voltages at either extreme
may result in system instability.
– Heat TRIACs can be checked by purchasing a 24 Vac LED and connecting to the TRIAC output
.
If the
24 Vac LED does not light up, replace the UC400 controller.
NOTICE:
Equipment Damage!
The UC400 controller outputs are switched to ground. Do not jumper 24 Vac to binary output
TRIAC(s) because damage will occur.
• Move electric heat relay wires from the UC400 controller and apply 24 Vac directly.
• Electric heat stage should energize. If it does not, then check the wir
ing, safeties, electric heat
contact, or replace any necessary components.