Schreiber Chillers 150ACsf - Manual (Page 11)

SPECIAL INSTRUCTIONS
WATER PUMP
The water pump is controlled by the manual switch for off and on operations. The motor
on this pump has a built-in overload protection, as do all the motors in our system.
ELECTRICAL CONTROLS - Control Circuit 24 Volts
The control circuit for the refrigeration system has several controls wired in series. First
are the high and low pressure switches that are mounted in the control panel.
High Pressure Switch - The high-pressure switch will shut off the refrigeration system
in the event the refrigerant pressure is too high. High pressure can be caused by the
condenser becoming restricted, by foreign material on the outside surface of the
condenser, or if the fan motor is not running. If the high-pressure limit switch should cut
out, there is a manual reset switch, which is located at the control panel on the right
side. In order to reset this switch, the disconnect switch and the switch must be turned
off and the control panel door must be open. If and when the high-pressure switch is off,
check the "Trouble Shooting" chart for diagnosis.
Low Pressure Switch - The low-pressure switch will cut out at any time the refrigerant
pressure in the refrigeration system is below 25 psi. Low psi can be caused by a freeze
up in the water tank, a leak in the refrigeration system, if the system is low on Freon (R-
22), or if there is any sort of restriction in the system. If the switch cuts out, it will
automatically reset. Never try to adjust the high and low-pressure switches or by-pass
them, or serious damage to the system will result. Adjustment should only be made
after the internal pressure of the refrigeration system has been read.
Temperature Controller - The second control of the circuit is the temperature
controller. It controls the cycling of the refrigeration system. Once this control is set, it
will control the cycling of the unit automatically. Do not set it below freezing unless the
proper amount of antifreeze is put into the unit. Because antifreeze is a poor conductor
of heat, never add more than necessary.
Manual - The third control on the circuit is the manual compressor switch. It is only used
to turn the refrigeration system on or off.
The fourth part on the circuit is the overload protection on the compressor. It will open if
the unit becomes low on refrigeration or if the improper voltage is used. This part of the
circuit is an automatic reset.
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150AC