Ice-O-Matic ICE0250 Series Refrigeration System, Refrigerant Cycle and Components, Compressor

ICE Series Refrigeration System

Refrigerant Cycle and

Components

Before diagnosing the refrigeration system, it is very important that the refrigerant charge be correct.

Whenever the refrigeration system has been opened, the filter-drier must be replaced and the proper refrigerant charge must be weighed in. See refrigerant charge data on page A5–A8.

Refrigerant Pressures

The suction pressure at the

beginning of the freeze cycle can vary +/- 10 psi

(.7 bar) depending on operating conditions. Reference Chart on page E10-E13. Pressures less than this may indicate an undercharge. The discharge pressure on water-cooled units should be 250 psi (17.01 bar) for R404a units and 150 psi (10.21 bar) for R134a units. The discharge pressure on air cooled units will vary with ambient conditions but will typically run higher than water cooled units. Remote condensers located in ambient temperatures below 70°F (21°C) will typically run a lower discharge pressure. See Mixing Valve later in this section.

Refrigerant in a gas state is pumped throughout the refrigeration system by a hermetic compressor to the condenser. Heat is removed from the refrigerant either by forced air movement through an air-cooled condenser or transferring heat from the refrigerant to water through a water-cooled condenser. The refrigerant changes to a liquid when cooled.

The refrigerant in a liquid state passes through a filter drier. The filter drier traps small amounts of moisture and foreign particles from the system. The filter drier must be replaced whenever the refrigeration system is opened or if the refrigerant charge has been completely lost.

Compressor

The compressor runs during the entire cycle. If the valves in the compressor are damaged, the compressor will be unable to pump refrigerant efficiently. Damaged valves are usually the result of another problem in the refrigeration system such as liquid refrigerant returning to the compressor, oil slugging or high head pressure. When a compressor is replaced it is important that the refrigerant charge be weighed in and the system checked for proper operation to prevent a repeat failure.

An inefficient compressor will usually have a higher than normal suction

pressure at the end of the cycle. The freeze cycle will be longer than normal and/or the harvest cycle may be excessively long. Check the compressor amperage draw 5 minutes into the freeze cycle. If the compressor amp draw (Reference data plate on ice machine back panel) is less than 70% of rated full load amps, the compressor may be inefficient. These symptoms may also be caused by other problems, therefore it is important to use the troubleshooting trees when diagnosing a problem. See Electrical System for more information on the compressor and compressor start components.

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