16 VAV-SVX03A-EN
Symptom Probable Cause Recommended Action
Fan not running Faulty connection Check wiring diagrams and inspect all connections.
Incorrect voltage input Compare actual voltage with supply requirement.
Faulty fan motor Check motor and power to the fan motor. If power is present and fan does not run, replace the motor.
Fan motor noise Incorrect voltage input Compare actual voltage input with supply requirement.
Loose fan wheel Adjust and tighten fan wheel
Low cfm to unit Supply fan not providing Adjust supply fan speed. Check for proper rotation.
adequate cfm
Leaky duct work Repair leak.
Dirty Filters Replace air filters
Improper cfm to zone Debris is jamming valve Clear valve damper travel.
Damage to valve casing Repair casing or replace valve.
Improper wiring Check unit diagrams for correct connection.
Faulty circuit board Check and replace if necessary.
Faulty valve motor Check and replace if necessary.
cfm setting incorrect Recalibrate circuit board.
Incorrect air temperature Incorrect wiring to reheat coil Check and replace if necessary. Compare wiring with diagram on unit.
delivered to the zone
Faulty zone sensor Check for correct zone sensor resistance.
Faulty circuit board Recalibrate and replace if necessary.
Incorrect supply air temperature Check leaving air temperature from air handling unit.
Coils do not engage on Faulty relay or Triac Check for voltage to heating coil and relay(s). Verify supply voltage matches coil voltage.
Call for heat
Board not calibrated Calibrate.
Room temperature differs Erratic zone sensor Check zone sensor voltage 12-volts DC between terminals 1 and 3. Check DC voltage at zone sensor
from reading on zone terminal 2 and 3 (6 volts DC). Turn zone sensor to full heating voltage; it should be equal to or less
Sensor (PI) 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.
Zone sensor miscalibrated. Check calibration of zone sensor. See also calibration section.
Troubleshooting
Tools 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.
WARNINGWARNING
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