Vav Electric Heat Stage Failure - Trane Tracer Uc

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VAV Electric Heat Stage Failure

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 outputs do not energize, check the following:
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Equipment Damage!
The UC400 controller outputs are switched to ground. Do not jumper 24 Vac to binary output
TRIAC(s) because damage will occur.
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VAV-SVX07B-EN
– The voltage selection switch still remains fully clockwise.
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.
Zone temperature is at or above the heating setpoint. Increase the UC400 controller heating
setpoint.
Verify 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
minimum heating flow.
Heat relays have failed.
– If the UC400 controller is calling for electric heat (viewed in the Status screen), 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
the power input to on XFMR 24 Vac input and
should be between 20.4 and 27.6 Vac (24 Vac catalogued). 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.
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 wiring, safeties, electric heat
contactor, or replace any necessary components.
WARNING
. It should have 24 Vac. If it does not, measure
of the UC400 controller. The supply voltage
NOTICE:
Troubleshooting
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