Schreiber Chillers MC75WC - Manual (Page 3)

MC75 - WC
TRUE MOLD CONTROL, WITH A NARROW BAND
DESCRIPTION OF IT’S OPERATION
1 THE TRUE MOLD CONTROL is designed as a source of high temperature water for
controlling the temperature of molding equipment. This system has a stainless steel water
reservoir, which is controlled by a narrow band controller that holds the water reservoir to a
close temperature tolerance.
i) There is an electric heater installed in the water reservoir tank, which provides the
heating. The cooling is done by an outside source of cooling water (tap water,
cooling tower or a water chiller) when the unit reaches an over temperature then the
narrow band controller will allow the solenoid to open causing cooled water from
one of these cooling source to flow cooled water over the cooling heat exchanger.
There is a thermocouple sensing the return water temperature. When the correct
temperature is reached the cooling water solenoid valve will close. This is a 24V
solenoid.
ii) The main components of the mold control are: stainless steel water reservoir, water
pump, heater element, cooling water solenoid valve, water pump, chilled water heat
exchanger, and the narrow band controller.
iii) There is a manual low voltage switch on the front electrical panel. This switch
controls the 24 volt control circuit to the unit. This switch is to be used to turn this unit
off and on. Please note this switch only controls the low voltage.
2 Control System: All functions of unit is controlled by a solid state narrow band controller*.
The water pump motor can be started with a switch on the controller. When the water pump
is running the temperature of the discharge water will displayed on the controller. The return
water has its own temperature display. When the return water is 2
0
F above the set point
the cooler supply water will open allow chilled water to flow through the chilled water heat
exchanger. This will cool the water to the mold to the proper temperature.
i) The unit has a high temperature cut-out. If the water temperature goes over 250
0
F,
the controller will cut out the heating element.
ii) There is a low water float installed in the reservoir. If the water reaches a low level,
the float will cut the system out till the reservoir is filled to proper level.
*There is a rotary off & on switch, which controls the Electrical power to the
unit.
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