Wittern VendNet 3576M - Unit Operation Troubleshooting; Noisy or Vibrating Unit Diagnosis; Unit Short Cycling Causes; Continuous Unit Operation Issues

32 | MULTI- ZONE / FROZEN FOOD VENDOR • 3576 • 4222618A
NOISY OR VIBRATING UNIT
1. Components rubbing or touching each
other.
♦ Check fan blades and motor.
♦ Loose shrouds and harness.
♦ Copper tubing.
♦ Loose or unsecured parts.
♦ Dirty condenser fan blades.
2. Worn or aged compressor grommets.
3. Compressor.
♦ Bad valves.
♦ Slugging.
♦ Bad windings (Refer to Table 1 and
schematic on page 29.).
♦ Voltage too low.
UNIT SHORT CYCLES
• Defective condenser fan.
• Dirty or blocked condenser coils.
• Dirty or blocked air filter.
• Dirty or blocked inlet or outlet screens.
• Defective overload (motor protector).
• Temperature sensor is defective or not
mounted in the correct spot.
• Temperature setting set too warm.
See Temperature Control section and
Factory Default Settings section of this
manual.
• Defective control board.
UNIT OPERATES LONG OR CONTINUOUSLY
1. Airflow restricted.
♦ Clogged or blocked inlet screen, air
filter, or outlet screen.
♦ Exhaust area blocked. Vending
machine too close to wall.
♦ Airflow blocked by product in front
of evaporator or air duct openings.
♦ Faulty evaporator motor or blades
causing coils to ice.
♦ Loose connections on evaporator
motor. Motor not running.
2. Refrigeration relay shorted. Switch the
controller to Service Mode, and then
verify that relay turns off by using the
TEST RELAY menu.
3. Gasket leak around main door or
delivery door.
4. Excessive load: After loading, unit
runs longer to pull out excessive heat
from product.
5. Shortage of refrigerant or restriction.
6. Faulty controller.
7. Ambient air temperature and relative
humidity exceed manufacturer’s
operational standards.
8. Defective temperature sensor or
sensor has been moved or remounted
to wrong spot.
REFRIGERATED SPACE TOO COLD
1. Refrigeration relay bad. Switch the
controller to Service Mode, and then
verify that relay turns on by using the
TEST
RELAY menu. Check relay
terminals for continuity with an
ohmmeter.
2. Faulty controller.
REFRIGERATED SPACE TOO WARM
♦ Condenser airflow restricted.
♦ Plugged or dirty condenser.
♦ Condenser motor or blades bad.
♦ Blade stuck.
♦ Condensing space restricted.
♦ Unit placed too close to a wall.
♦ Compressor - bad valves.