Omcan IC-CN-0040 Manual De Instrucciones página 18

Troubleshooting
capacitor is defective, the compressor will not start properly. The run capacitor is an electrical storage device
used to improve the productivity and efficiency of the compressor. Before checking a capacitor, it should be
discharged by shorting across the terminals. If a run or start capacitor is cracked, leaking or bulging it should
be replaced. If a capacitor is suspected of being defective, it can easily be checked by replacing it with a
capacitor of the correct size, which is known to be working. If the compressor starts and runs properly, replace
the original capacitor. A capacitor tester can also be used.
Start Relay
The start relay breaks the electrical circuit to the start windings when the compressor motor speed increases. If
the relay is defective, the compressor will not start or it may start but will run for a very short time.
A compressor relay can be checked by removing the relay and checking the relay contacts for damage and
check for continuity across the closed relay points. Check the relay coil with an ohmmeter. If no continuity is
read, replace the relay.
Thermostatic Expansion Valve (TXV)
The thermostatic expansion valve measures the flow of refrigerant into the evaporator changing its state
from a high pressure liquid to a low pressure liquid. This drop in pressure causes the refrigerant to cool. The
cooled refrigerant absorbs heat from the water circulating over the evaporator. As the evaporator fills with
liquid refrigerant, the evaporator becomes colder. The flow of refrigerant into the evaporator is controlled by the
temperature at the outlet of the evaporator. The expansion valve bulb, mounted to the top of the suction line,
senses the evaporator outlet temperature causing the expansion valve to open or close. As ice forms on the
evaporator, the temperature drops and the flow of refrigerant into the evaporator decreases, resulting in a drop
in suction pressure. The evaporator should become completely flooded (filled with liquid refrigerant) during
the freeze cycle. A completely flooded evaporator will have a uniform freeze pattern (ice formation across the
evaporator). A starved evaporator (not enough liquid refrigerant) will have poor or no ice formation at the top of
the evaporator, and the tube(s) exiting the evaporator will not frost. All tubes should be frosted approximately
5 minutes from the start of the freeze cycle. An expansion valve that is restricted or not opening properly will
starve the evaporator resulting in lower than normal suction pressure. A low refrigerant charge will also starve
the evaporator and cause low suction and discharge pressures. If not sure of the amount of charge in the
system, the refrigerant should be recovered and the correct charge be weighed in before a defective valve can
be diagnosed. If the evaporator is starved but the suction pressure is higher than normal, the TXV is not the
problem, refer to the above charts. If the TXV sticks open or if the thermal bulb is not making good contact with
the suction line, the flow of refrigerant into the evaporator will be too great and liquid refrigerant will flood the
compressor. The suction pressure will remain higher than normal and the machine will remain in an extended
freeze cycle. Ice will build evenly but will be very thick.
REFERENCE
Item Number Model Number Description Manufacturer Model Number
Ice Maker 88 lbs. / 40 kgs. Capacity
27936 IC-CN-0040 AZ-120L
115V/60/1 UL cUL
18