Refrigeration System - Carrier Miracool Owner's Manual

TABLE 3 – REFRIGERATION SYSTEM SERVICE AND ANALYSIS CHART
MALFUNCTION
Compressor will not start
- no hum -
Compressor will not start
- hums but trips on overload
protector.
Compressor starts but does not
switch off of start winding.
Compressor starts and
runs, but short cycles on
overload protector.
Unit runs OK, but short
cycles.
Unit operates long or
continuously.
Start capacitor open, shorted or
blown.
Run capacitor open, shorted
or blown
Relay defective or burned out
Space temperature too high
Cooler freezing beverage
Unit noisy

REFRIGERATION SYSTEM

POSSIBLE CAUSE
1. Line cord not plugged in.
2. Fuse removed or blown.
3. Overload protector tripped.
4. Temp control stuck in open position.
5. Wiring improper or loose.
1. Low voltage to unit.
2. Relay failing to close
3. Starting capacitor defective.
4. Improperly wired.
1. Low voltage to unit.
2. Relay failing to open.
3. Run capacitor defective.
4. Compressor mounting winding is open or
shorted.
1. Additional current passing through overload
protector.
2. Low voltage to unit.
3. Overload protector defective.
4. Run capacitor defective.
5. Excessive discharge pressure.
6. Compressor too hot - return gas hot.
1. Overload protector.
2. Cold control.
3. Overcharge.
4. Air in system.
5. Undercharge.
1. Dirty condenser.
2. Shortage of refrigerant.
3. Temperature control contacts stuck or frozen.
4. Evaporator coil iced.
5. Restriction in refrigeration system.
1. Relay contacts not opening properly.
2. Low voltage to unit.
3. Improper relay.
1. Improper capacitor.
2. Excessively high line voltage (110% of rated
max).
1. Incorrect relay.
2. Line voltage too high or too low.
3. Relay being influenced by loose vibrating
mounting.
1. Control setting too high.
2. Overcharged with refrigerant.
3. Inadequate air circulation.
1. Temperature control
1. Loose parts or mountings.
2. Tubing rattles.
3. Bent fan blade causing vibration.
4. Fan motor bearings worn.
1. Plug in the cord.
2. Replace fuse.
3. Refer to electrical section.
4. Repair or replace temp control.
5. Check wiring against diagram.
1. Determine reason and correct.
2. Determine reason and correct, replace if
necessary.
3. Determine reason and replace.
4. Check wiring against diagram.
1. Determine reason and correct.
2. Determine reason and correct, replace if
necessary.
3. Determine reason and replace.
4. Determine cause, correct, and replace
compressor.
1. Check wiring diagram. Check for added fan
motors, pumps, etc. connected to wrong side of
protector.
2. Determine reason and correct.
3. Check current, replace protector.
4. Determine reason and replace.
5. Check ventilation, restrictions in cooling medium,
restrictions in refrigeration system.
6. Check refrigerant charge (fix leak if necessary).
Check airflow across condenser.
1. Check wiring diagram for correct wiring.
2. Differential set too close.
3. Reduce refrigerant charge.
4. Recover and recharge.
5. Fix leak and recharge with refrigerant.
1. Clean condenser.
2. Fix leak, add charge, correct charge.
3. Replace temperature control.
4. Defrost.
5. Determine location and remove.
1. Replace relay.
2. Determine reason and correct.
3. Replace.
1. Determine correct size and replace.
2. Determine reason and correct.
1. Check and replace.
2. Determine reason and replace.
3. Remount rigidly.
1. Reset control.
2. Recover refrigerant and recharge with proper
charge specified on data plate.
3. Improve air movement.
1. Reset control.
1. Find and tighten.
2. Reform to be free of contact.
3. Replace blade.
4. Replace motor.
10
SOLUTION