Electrical Connections
2
Extra-Low Voltage Control Wiring
Control interlock between the control enclosure and the indoor unit(s) is required. It is connected
between 70 and 71 on the wire raceway in the compressor compartment of the indoor unit and the
control box. Multiple indoor units may be connected in parallel if the controlled pumps will feed them
all.
• Extra-low voltage non-safety control wiring must be a minimum of 16 GA. (1.665 mm
2
) for up to
75 feet (22.9 m), or not to exceed 1 volt drop in control line.
• Install extra-low voltage control wiring (24 volt) from terminals 70 & 71 from the indoor-cooling
unit to terminals 70 & 71 of the control enclosure.
• Extra-low voltage control wiring should also be installed between terminals 24 and 50 from the
control enclosure to the indoor-cooling unit's common alarm or other alarm location for loss of flow
indication.
• Install extra-low voltage control wiring between the auxiliary terminals on control panel to termi-
nals 70 and 71 on drycooler.
• The flow switch wiring should be connected to terminals 77 and 74.
• Provide 3-phase line voltage to power block in control enclosure.
• Install optional field-supplied disconnect if desired.
• Run 3-phase line voltage from the control box to each individual pump motor.
Flow Switch Installation (Pump Package Installations Only)
Mount the flow switch in a section of coolant supply/return piping where there is a straight run of at
least five (5) pipe diameters on each side of the flow switch.
• The switch should be mounted so the terminals or wire leads are easily accessible for wiring.
• Mount the flow switch in a standard 1 in. x 1 in. x 1 in. tee for 1-in. pipe installation. Use a reduc-
ing tee for larger sizes of pipe to keep the flow switch close to the pipe and provide adequate pad-
dle length in the flow stream.
• Screw the flow switch in position so the flat of the paddle is at a right angle to the flow. The arrow
on the side of the case must point in the direction of the flow.
• The flow switch may be mounted in a horizontal pipeline or a vertical pipeline with upward liquid
flow. It is not recommended for installations where the flow is downward. When mounted in a ver-
tical pipe with upward flow, the switch will trip at a slightly higher flow due to the effect of the
gravity on the switch mechanism.
