Vav Series Fan Failure - Trane Tracer Uc

Troubleshooting

VAV Series Fan Failure

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 fan output does not energize, check the following:
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– Check damper actuator motor by applying 24 Vac directly to common (blue) and jumper
closed (red) wire to ground to drive damper closed. Damper should drive closed. If not,
replace damper actuator.
– The UC400 controller outputs are switched to ground via low-side triac solid-state switches.
Because the binary outputs are triac based, the state of the output is difficult to check directly
with a digital multi-meter (DMM). To check state of the output with a DMM, the output must
me loaded with a 12VA max load. For example, a fan relay. 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.
Important: Do not jumper 24 Vac to BO8 and BO9 because damage will occur to the UC400
binary output circuitry.
Verify the output configuration in the UC400 controller setup screen. Unit needs to be
configured as series fan.
Outputs on the UC400 controller are configured as normally closed. Verify the output
configuration in the UC400 controller setup screen.
Note: Series fan-powered units in the occupied mode have the fan continuously energized.
Tracer SC has the fan output disabled. Check overrides to ensure they are not inhibiting fan
operation.
A flow override exists locking out the fan output. Ensure that either Tracer SC or the Tracer TU
service tool has released fan disable override.
If the UC400 controller is calling for the fan to be ON (viewed in the Status screen), and if it is
not, then check the TRIAC output wiring and relay output.
– Override damper open.
– Verify that the fan cycles ON.
– Check BO4 to common
on XFMR 24 Vac input and
between 20.4 to 27.6 Vac (24 Vac catalogued). However, voltages at either extreme may result
in system instability.
– 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.
– Remove fan wires from the UC400 controller and apply 24 Vac directly to fan relay wires.
– Fan relay should energize. If it does not energize, check wiring. If wiring is correct, replace
fan relay.
WARNING
. It should have 24 Vac. If it does not, measure the power input to
of the UC400 controller. The supply voltage should be
VAV-SVX07B-EN