Ice-O-Matic RGA0501-HM, Installation Manual

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8
Component Descriptions
Mixing Valve (Headmaster, Low Ambient Control Valve)
This valve serves as the head pressure regulating valve. It contains a pre-determined charge of nitrogen in
the valve bellows. When the temperature at the condenser is
above 70°F (21°C), the refrigerant flow from the compressor is
directed by the mixing valve through the condenser and into
the receiver. When the temperature at the condenser drops
below 70°F (21°C), the pressure in the bellows of the mixing
valve becomes greater than the pressure of the liquid
refrigerant coming from the condenser. This change allows
the valve to partially restrict the flow of refrigerant leaving the
condenser and allows discharge gas to by-pass the
condenser and flow directly into the receiver, mixing with the
liquid refrigerant from the condenser. The amount of
discharge gas that bypasses the condenser increases as the
ambient temperature decreases. This action of the mixing
valve allows the discharge pressure to be maintained at approximately 217 psi during low
ambient conditions. If the refrigerant system is undercharged and the ambient temperature is below 70°F
(21°C), the mixing valve will not work properly. The mixing valve will allow too much refrigerant to bypass
the condenser.
Receiver
The quantity of liquid refrigerant in the receiver will vary with the temperature at the condenser coil.
Liquid Line Solenoid and Pump Down Low Pressure Control
ICE Series ice machines
When the bin is full or the ON-OFF switch is turned to the OFF position, the liquid line
solenoid valve closes and the system begins to pump down. When the low pressure
reaches 10-20 psi, the pump down low pressure control opens and the contactor
shuts the machine off.
As the ice is removed from the bin or the ON-OFF switch is turned to the ON position, the liquid
line solenoid valve opens and the high side and low side pressures begin to equalize.
When the low side pressure reaches 50-75 psi, the pump down low pressure control closes and
the machine begins a freeze cycle. When the machine is off for extended periods of time, it will
pump down approximately once every hour. This is due to the equalization of pressures during
the off cycle resetting the pump down low pressure control. It is a normal function of the
refrigeration system.
CIM Series ice machines
When the bin is full or the machine is turned OFF, the machine will shut down 30 seconds after the pump
down initiation. The machine will pump down once every 2 hours, for 15 seconds during normal operation.
Condenser Fan Motor
The condenser fan motor is a single speed, permanent split capacitor motor and should be wired according
to the wiring diagram. The motor is permanently lubricated for long service life.