The LiebertOutdoor Control Enclosure is designed to be used with a Liebert condenser or drycooler to control one or more pump and/or fan motors. The enclosure is rated NEMA 3R when installed as shown in Figure 114.
Figure 114Liebert Outdoor Control Enclosure installed NOTE
For glycol solution preparation and periodic testing, follow manufacturer’s recommendations.
Do not mix products of different manufacturers.
Table 52 Volume in standard Type "L" copper piping Diameter (in.) Volume
Outside Inside gal/ft l/m
1-3/8 1.265 0.065 0.81
1-5/8 1.505 0.092 1.15
2-1/8 1.985 0.161 2.00
2-5/8 2.465 0.248 3.08
3-1/8 2.945 0.354 4.40
3-5/8 3.425 0.479 5.95
4-1/8 3.905 0.622 7.73
Figure 115 Flow rate, 10 hp, 3500 rpm pump package, Model # 9A31258G3 in aluminum enclosure
Table 53 Liebert Outdoor Control Enclosure specifications
Model HP Size Impeller
Cabinet Size- in (mm) Discharge Suction Length Width Height D10ANTS1317
10 2 x 1.5 x 7 6.44 1.5 FPT 2.0 FPT 14 41.3
SAFM-7820-11 Rev. 2
Flow Rate (GPM)
T otal Head (Ft of W ater)
0 20 40 60 80 100 120 140 160 180 200
0 100 200 300 400 500
Ensure that the tank included in the design has a minimum volume of 6% of the total system volume.
6.14.1 Electrical Connections
6.14.2 Hazardous Voltage Power Supply Wiring Wire per national and local electrical codes.
Hazardous voltage electrical service is required at the location of the control enclosure. Use the knockouts provided at the bottom of the enclosure. This power supply does not have to be the same voltage as the Liebert indoor unit. This separate power source may be 110V, 208V, 230V, 460V or 575V, single-phase or three-phase, 60Hz; or it may be 200V, 230V, 380V or 415V, single-phase or three-phase, 50Hz as appropriate.
Install a field-supplied disconnect as required per local and national codes.
Figure 116Dimensions and knockout sizes, 36-inch models
Risk of electric shock. Can cause injury or death.
Disconnect all local and remote power supplies before working within.
7/8" (.875mm) Knockout Knockouts
7/8" (.875mm) 1-1/8" (28.6mm) 1-3/8" (34.9mm) Knockouts
7/8" (.875mm) 1-1/8" (28.6mm) 1-3/8" (34.9mm) 1-3/4" (44.45mm)
(28.6mm) Knockout 37-9/16"
(954mm) 7/8" (.875mm)
Knockout 1-15/16" (49.2mm)
6.14.3 Extra-Low Voltage Control Wiring
Control interlock between the control enclosure and the indoor unit(s) or other source(s) is required.
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 mm2) for up to 75 feet (22.9m), or not to exceed 1V drop in the control line.
• Install extra-low voltage control wiring (24V) from Terminals 70 & 71 on the wire raceway in the compressor compartment of the indoor 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 the control panel to Terminals 70 and 71 on the drycooler.
• The flow switch wiring should be connected to Terminals 77 and 74.
• Provide line voltage to power block(s) in control enclosure as shown in the electrical schematic.
• Install optional field-supplied disconnect if desired.
• Run three-phase line voltage from the control box to each individual pump motor.
6.14.4 Dual Pump Package Flow Switch
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" x 1" x 1" tee for one-inch pipe installation. Use a reducing tee for larger sizes of pipe to keep the flow switch near the pipe and to provide adequate paddle length in the flow stream.
• Screw the flow switch in position so the flat part 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 must be mounted in a horizontal pipeline.
6.14.5 Dual Pump Controls Sequence of Operation
On a call for cooling, the compressor contactor and/or the Econ-O-Coil relay in the Liebert unit is energized. The relay and contactor are in the Liebert indoor evaporator section. Each compressor contactor has a side switch wired in parallel with the Econ-O-Coil relay and is responsible for closure of the low-voltage pump-control circuit.
This low-voltage circuit has a series of contactors, relays, selector switch and a flow switch. This circuit controls the start of the pumps and provides contact closure to interlock the drycooler(s) control circuit. Once the circuit is closed, 24V is passed to the pumps control circuit and the auxiliary relays are energized, closing the drycooler(s) control circuit.
Pump P1 is factory-set to be the primary pump (Selector Switch 1-2). Voltage then passes through the normally closed contacts of the R2 relay (standby pump relay), through the current overloads and to the #1 pump contactor. At this point, the #1 pump and appropriate drycoolers are running.
When the pump establishes flow, it opens the system flow switch. The pump has approximately 10 seconds to establish full flow. If it does, the system will run in this state until the call for cooling is satisfied and the circuit drops out. If this pump cannot establish flow or if it has been running and fails, the flow switch will close and energize an adjustable relay, typically set for 10 seconds.
Once this relay times out, it energizes the R2 switch over relay. This relay will drop out the voltage to the #1 pump contactor and energize the #2 pump contactor. Along with the R2 relay the AL relay (alarm relay) will energize. This will provide a set of closed contacts for remote indication of the switch-over situation.
Once the problem with the lead pump is repaired, the controls must be reset. To reset the control box, turn Off the main power to the control box and then restore the main power to the control box. Pump P1 then becomes the primary pump again.