VendNet ST 3000, Service Manual

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S T / V T V E N D O R
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NOTE
:
The sealed hermetic system should not be worked on outside the Factory Service Center
.
REFRIGERATION TROUBLESHOOTING
COMPRESSOR WILL NOT START
Problem Possible Causes/Actions
1.
Vendor not plugged in.
2.
Tripped breaker or blown fuse.
3.
Faulty wall outlet
4. Faulty (short or open) power cord. Check power cord with a Multi-Meter.
5. Improper wiring.
6. Low voltage
Check the power source with a volt meter. Minimum of 103VAC for 115VAC, 60HZ,
Minimum of 195VAC for 230VAC, 50Hz.
7. Overload defective
Overload is tripping to fast.
Check overload with a Multi-Meter.
8. Start relay defective Check start relay with a Multi-Meter.
9. Compressor has open windings Check compressor windings with a Multi-Meter.
10. Defective refrigeration relay

Switch the controller to Service Mode then verify that the relay turns on by
using the Test Relay menu.

With refrigeration relay turned on in the Test Relay menu. Check relay
terminals 1 to 0 for 24VDC with a Multi-Meter. If power is present relay is bad.
11. Defective control circuit
Unplug power to the vendor. Open the power panel. Use insulated jumper wires to
short the wire terminals on
Relay 1 ; between 2 and 4 and between 6 and 8. Restore
power to the vendor. The compressor should start. If it does there is a problem in
the control circuit.
12. Defective door switch Check for proper door switch operation.
COMPRESSOR TRIPS ON OVERLOAD
1.
Improper voltage
Check voltage for 5-10% above or 5% below machines rated voltage. Check power
source with a Multi-Meter.
2. Overload defective
Overload tripping to vast.
Check overload with a Multi-Meter.
3.
Relay defective
Relay Won’t open after starting.
Check relay with a Multi-Meter.
4. Compressor has shorted winding Check compressor windings with a Multi-Meter.
NOISY OR VIBRATING UNIT
1.
Components rubbing or touching
each other

Check fan blades and motor.

Loose shrouds and harness.

Copper tubing rubbing.

Loose or unsecured parts.

Dirty condenser fan blades.
2. Worn or aged grommets Check grommets.
3. Compressor

Bad valves.

Slugging.

Bad windings (see Figure 21. Compressor Schematic).

Low voltage.
UNIT SHORT CYCLES
1. Defective overload Check overload with a Multi-Meter.
2. Faulty condenser fan
3. Airflow restricted

Dirty or blocked condenser coils

Dirty or blocked air filter

Dirty or blocked inlet or outlet screens