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Troubleshooting
Turn off all power to the unit before conducting any
troubleshooting procedures unless the procedure
specifically requires the system to operate. For
troubleshooting purposes, the system may be operated
with the doors open by using vice-grip pliers to turn the
shaft of the main power disconnect switch to the "On"
position.
Table 7.
Troubleshooting
SYMPTOM
Suction Pressure Too Low
Evaporator Coil Ices
Evaporator Fan(s) Fail to Start
Control is Erratic
Condenser Pressure Too High
SS-SVX002B-EN
Note: When the switch is turned on, high voltage will be
PROBABLE CAUSE
a. Loss of refrigerant (bubbles in sight glass). Locate leak and repair. Recharge system.
b. Expansion valve stuck or obstructed (short
cycle or continuous running).
c. Clogged drier/strainer (feels cold).
d. Dirty air filters (reduced airflow).
a. Low airflow.
b. Temperature setting too low
c. Discharge air short circuiting back to return.
d. Low refrigerant charge.
a. Power failure.
b. Motor starter protector tripped.
c. Control transformer circuit breaker tripped.
d. Defective contactor
e. No control signal to fan(s).
f. EC fan's internal overheat protection
interrupted fan motor operation
Wiring improperly connected or broken.
a. Non condensable gas or air in the
refrigeration system.
b. Condenser air intake is blocked.
c. Overcharge of refrigerant.
present inside the cabinet. Exercise caution to
prevent injury. Keep hands, clothing and tools clear
of the electrical terminals and rotating
components. Ensure that your footing is stable at
all times.
RECOMMENDATION
Remove and clean or replace valve.
Replace with new drier/strainer.
Clean/replace filters.
1.
Check filters. Replace as needed.
2.
Check for and clear any obstructions across
or in the (supply) discharge airstream.
3.
Check evaporator fan is operating
4.
Check fan speed. Increase if needed using
the system controller.
Increase temperature set point. (68°F min.).
Check discharge airflow orientation in the
conditioned space.
Find leak, repair and recharge system.
1.
Check main power source voltage.
2.
Check power input cable.
Reset motor starter protector and check
amperage of motor.
Check for short circuit or ground fault, if none,
reset circuit breaker.
Repair or replace.
Check the Control I/O Board for a Modbus
control signal to the fan(s). Refer to the electric
drawing to determine the correct I/O board
terminal numbers. This must be done within 15
seconds of turning the disconnect switch "On" or
the controller will go into "Air Proving Alarm"
mode.
Determine the cause of the interruption and
correct. Possible causes are:
1.
Blocked rotor
2.
Low supply voltage > 5 seconds
3.
Loss of phase > 5 seconds
After causes 1, 2, and 3 above are corrected, the
motor will automatically reset.
After causes 4 and 5 below are corrected, the
fan(s) must be manually reset by turning off
power for 20 seconds:
4.
Over temperature of electronics
5.
Over temperature of motor
Check wiring against schematic diagram.
Recover refrigerant. Replace drier/strainer.
Evacuate to 50 microns and recharge.
Remove debris and clean condenser.
Reclaim excess refrigerant from system.
43
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