Installation and Maintenance Manual

82 VAV-SVX07A-EN
Troubleshooting
• Check BO4 to common . Should have 24 VAC; if it does not, measure the power input to
on XFMR 24 VAC input and of 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.
• Triac can be checked with purchasing a 24 VAC LED and see if it lights up on call for fan the
Tracer UC400 controller. If LED does not light up replace the Tracer UC400 controller.
• Remove fan wires from UC400 and apply 24 VAC directly to fan relay wires.
• Fan relay should energize. If it does not energize check wiring. If wiring is OK replace fan
relay.
Notice:
Equipment Damage!
The Tracer UC400 controller outputs are switched to ground. Do not jumper 24 VAC to binary
output TRIAC(s) because damage will occur.
8. After all checks have been completed, check motor fan winding integrity and bearing failure.
PSC Variable Speed Motor Check Out
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.
If PSC Variable speed motor control is not changing speed of the motor inspect the following:
• Wires connected improperly.
• Check wiring to make sure speed control is wired correctly. See Figure 37, p. 86 and
Figure 44, p. 93 for wiring schematic.
• Check voltage selection switch on side of variable speed motor control.
• Should be set for motor voltage.
• To check speed control.
• Turn voltage selection switch fully CCW.
• Turn motor speed control potentiometer fully CCW.
• Motor should remain off.
• Turn voltage selection switch fully CW.
• Motor speed control potentiometer still fully CCW.
• Measure motor voltage. Should be no more than 8 VAC lower than line voltage.
• With voltage selection switch still fully CW.
• Turn Motor speed control potentiometer slowly fully CW (HI).
• Should go to full speed smoothly.
Note: If it fails any of these tests replace PSC motor speed controller.