Troubleshooting; Tools And Equipment - Trane VariTrane Installation/ Owner Programming

Symptom Probable Cause
Fan not running Faulty connection
Incorrect voltage input
Faulty fan motor
Fan motor noise Incorrect voltage input
Loose fan wheel
Low cfm to unit Supply fan not providing
adequate cfm
Leaky duct work
Dirty Filters
Improper cfm to zone Debris is jamming valve
Damage to valve casing
Improper wiring
Faulty circuit board
Faulty valve motor
cfm setting incorrect
Incorrect air temperature Incorrect wiring to reheat coil
delivered to the zone
Faulty zone sensor
Faulty circuit board
Incorrect supply air temperature
Coils do not engage on Faulty relay or Triac
Call for heat
Board not calibrated
Room temperature differs Erratic zone sensor
from reading on zone
Sensor (PI)
Zone sensor miscalibrated.
T ools and Equipment
When repairing a VariTrane product (analog control), it is important to have the necessary tools and instruments.
1. 0-2" magnehelic gauge with fittings for two ¼" outside diameter (OD) tubing
2. Voltmeter
3. Four jumper leads
4. Small screwdriver 1/8" blade
Hazardous Voltage!
Certain tests or calibration procedures described in this section may involve working in close proximity to live electrical terminals.
Only qualified and licensed electrician or other properly trained in electrical safety when working with live voltage should
perform these procedures. Failure to follow all electrical safety precautions when exposed to live terminal could result in death
or serious injury.
16

Troubleshooting

Check wiring diagrams and inspect all connections.
Compare actual voltage with supply requirement.
Check motor and power to the fan motor. If power is present and fan does not run, replace the motor.
Compare actual voltage input with supply requirement.
Adjust and tighten fan wheel
Adjust supply fan speed. Check for proper rotation.
Repair leak.
Replace air filters
Clear valve damper travel.
Repair casing or replace valve.
Check unit diagrams for correct connection.
Check and replace if necessary.
Check and replace if necessary.
Recalibrate circuit board.
Check and replace if necessary. Compare wiring with diagram on unit.
Check for correct zone sensor resistance.
Recalibrate and replace if necessary.
Check leaving air temperature from air handling unit.
Check for voltage to heating coil and relay(s). Verify supply voltage matches coil voltage.
Calibrate.
Check zone sensor voltage 12-volts DC between terminals 1 and 3. Check DC voltage at zone sensor
terminal 2 and 3 (6 volts DC). Turn zone sensor to full heating voltage; it should be equal to or less
than 5.4 volts DC. Turn zone sensor to full cooling voltage should be equal to or greater than 6.5 volts
DC. If DC voltage is not attainable, replace the zone sensor.
Check calibration of zone sensor. See also calibration section.
Recommended Action
VAV-SVX03A-EN