Cornelius 500-Series Información técnica descargar pdf (Pagina 15)

Cornelius Ice Makers Training Manual

REFRIGERATION

Refrigeration System Operation

The WCC/WCF refrigeration system is a critical charge unit with very low superheat. Therefore, it is

important to not hook up refrigeration gauges unless absolutely necessary.

The system works by feeding refrigerant into the evaporator via a non-adjustable expansion valve. The

valve is connected at the lower port of the evaporator. The evaporator is constructed by winding a copper

evaporator tube around a stainless steel tube. The copper coil is soldered to the stainless tube to

improve heat transfer. The entire assembly is foam molded to insulate it.

Once the refrigeration system starts, the refrigerant enters the evaporator and pools in the lower coils

where it boils upward through the spiral creating the frost pattern on the inner surface. The refrigerant

exits the evaporator into the suction line.

The suction line is insulated immediately after the evaporator to prevent sweating and frost buildup. The

suction line is joined to the liquid line to create a heat exchanger that prevents frost-back to the compres-

sor. The A/C and W/C units have no receiver.

The difference between the evaporator inlet and outlet is only 4°F.

If recharging is necessary the system must be purged and charged to nameplate specifications.

Remote Units

The 1000 and the 700 series remote units are configured and controlled differently.

1000 Series Remote

The 1000 remote has the compressor located indoors and the condenser coil and fan unit located

remotely. The fan runs continuously. The only pressure-activated control is the low-pressure cutout,

located in the main unit.

This low-pressure suction-side switch is designed to open the control circuit to the contactor and shut the

compressor down after the pump-down cycle is complete. It is set to open at 0 psig and close at 20 psig.

The pump-down cycle is started by the opening of the low water reed switch, either of the bin controls, or

the manual pump-down switch. Once the circuit is open, the liquid line solenoid closes, trapping refriger-

ant in the receiver and condenser coil.

The low-pressure cutout waits for suction pressure to drop to 0.5 psig and opens the control circuit to the

compressor, shutting it down.

700 Series Remote

The 700 series remote has the compressor located in the condensing unit. This condensing unit is desig-

nated the WCU 600 (115 V) or WCU 601(208-230V). The WCU model is also available as an indoor

model for locations where this is desirable.

The 700 series controls its remote via a pump-down solenoid in the main unit and a low-pressure control

located in the remote. Once the ice level control (bin thermostat) or a safety control opens the control cir-

cuit, the liquid line solenoid closes and the condensing unit pumps the refrigerant back to its receiver.

The suction pressure goes into a vacuum and the low-pressure control in the remote shuts the unit down.

1 2 ... 10 11 12 13 14 15 16 17 18 19 20 ... 29 30

Sin comentarios

Cornelius 500-Series Información técnica Pagina 15