Vertiv Liebert STS2 Installer/User Manual
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Vertiv Liebert STS2 Installer/User Manual

Vertiv Liebert STS2 Installer/User Manual

1200a - 1850a chassis
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Liebert® STS2
Installer/User Guide
1200A - 1850A Chassis

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Summary of Contents for Vertiv Liebert STS2

  • Page 1 Liebert® STS2 Installer/User Guide 1200A - 1850A Chassis...
  • Page 2 The products covered by this instruction manual are manufactured and/or sold by Vertiv. This document is the property of Vertiv and contains confidential and proprietary information owned by Vertiv. Any copying, use, or disclosure of it without the written permission of Vertiv is strictly prohibited.

  • Page 3: Table Of Contents

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual TABLE OF CONTENTS 1 Important Safety Instructions 1.1 Overview of Manual 1.2 Safety Precautions 2 Unpacking and Inspections 2.1 External Inspections 2.2 Unloading and Handling 2.2.1 Handling Considerations 2.2.2 Unit Preparation 2.3 Internal Inspections 3 Location Considerations 3.1 Recommended Minimum Service Clearances...
  • Page 4 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 8.2.1 Normal (Preferred Source) 8.2.2 Transfer 8.2.3 Transfer Inhibit 8.2.4 Bypass 8.3 Operator Controls 9 Theory of Operation 9.1 General Description 9.1.1 Liebert® STS2 (Static Transfer Switch) 9.1.2 Source Transfer 9.1.3 Automatic Transfer/Retransfer 9.1.4 Emergency Transfer...
  • Page 5 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 12.1.2 Configuring the Vertiv™ Liebert® STS2 via the Terminal 12.1.3 Setting Bitpacked Options with the Terminal 12.1.4 Setting Event Masks with the Terminal 13 Vertiv™ Liebert® STS2 Touchscreen Display 13.1 Display Overview 13.2 Menu Overview 13.2.1 Security...
  • Page 6 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 14.1.7 Response Time 14.1.8 Environmental Requirements 14.2 System Components 14.2.1 Frame and Enclosure 14.2.2 Seismic Anchoring 14.2.3 Cooling 14.2.4 Access 14.2.5 Circuit Breakers 14.2.6 Doors 14.2.7 Color Graphical Display 14.2.8 RS-232 Port 14.2.9 Terminal Port Connections 14.2.10 RS-232 Interface Parameters...

  • Page 7: Important Safety Instructions

    1 Important Safety Instructions Save these instructions This manual contains important instructions that should be followed during the installation and maintenance of the Vertiv™ Liebert® STS2. WARNING! The unit is supplied by more than one power source. The unit contains hazardous voltages if any of the input sources are ON, even when the unit is in bypass.

  • Page 8: Overview Of Manual

    ISOLATE STATIC TRANSFER SWITCH (STS) BEFORE WORKING ON THIS CIRCUIT. 1.1 Overview of Manual The Vertiv™ Liebert® STS2 Installation, Operation and Maintenance Manual is organized in a logical progression so that you can follow the procedures in the order provided to get your Liebert® STS2 installed and running.

  • Page 9: Safety Precautions

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Specifications:provides specifications for the Liebert® STS2. Event Message Help Text:provides the help text for the various system event messages. This help is also available through the touchscreen interface. Maintenance:briefly discusses routine maintenance, provides proper torque settings for nuts and bolts, and provides the Vertiv contact information for technical support.
  • Page 10 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual This page intentionally left blank Proprietary and Confidential ©2025 Vertiv Group Corp. 1 Important Safety Instructions...

  • Page 11: Unpacking And Inspections

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 2 Unpacking and Inspections NOTE: Read the entire manual before installing and operating the unit. Upon receipt of the Vertiv™ Liebert® STS2, the installer should perform the following steps to ensure a high-quality installation.

  • Page 12: Handling Considerations

    The unit can be removed from the pallet before it is moved to its location. Complete the following steps to properly remove the Vertiv™ Liebert® STS2 from the shipping pallet: Set the pallet in a level area with enough room to maneuver and remove the unit.

  • Page 13: Location Considerations

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 3 Location Considerations The Vertiv™ Liebert® STS2 should be placed in a clean, cool and dry location. The Liebert® STS2 requires only front access for installation and maintenance. Back or side access is not required.
  • Page 14 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual This page intentionally left blank Proprietary and Confidential ©2025 Vertiv Group Corp. 3 Location Considerations...

  • Page 15: Locating The Vertiv™ Liebert® Sts2

    4.1 Leveling and Anchoring the Unit to the Floor The Liebert STS2 can be secured to a concrete floor using 4X M10 concrete anchors (field supplied). The Liebert® STS2 can be anchored to the concrete floor to ensure stability for the unit in the event of seismic activity.
  • Page 16 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual This page intentionally left blank 4 Locating the Vertiv™ Liebert® Proprietary and Confidential ©2025 Vertiv Group Corp. STS2...

  • Page 17: Power And Control Wiring

    The Vertiv™ Liebert® STS2 is designed for operation with 3-wire or 4-wire, solidly grounded sources only. For 4-wire operation of a 3-wire unit, the common source neutral must be connected to the Liebert® STS2. Circuit breaker cabinet specification shall be provided by original equipment manufacturer.

  • Page 18: System Grounding

    Item Description 1200A - 1850A Vertiv™ Liebert® STS2 Chassis Cabinet The molded case switches connected to the Liebert® STS2 are typically non-automatic circuit breakers that rely on the upstream and/or load overcurrent protection. Upstream overcurrent protection should be rated equal to or less than the rating of the Liebert®...

  • Page 19: Control Wiring Connections

    600V. The unit is set at the factory to match the nameplate voltage. Field adjustments are not necessary. If the unit needs to operate at a voltage other than what is listed on the nameplate, contact Vertiv or your local Vertiv representative.
  • Page 20 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual This page intentionally left blank Proprietary and Confidential ©2025 Vertiv Group Corp. 5 Power and Control Wiring...

  • Page 21: Options

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 6 Options This section discusses the options available for the Vertiv™ Liebert® STS2. The communications options are also discussed in Communication Interfaces on page 53 6.1 Programmable Relay Board The Programmable Relay Board (PRB) provides a means to trigger an external device when an event occurs in the Liebert®...

  • Page 22: Vertiv™ Liebert® Intellislot™ Unity-Dp Card

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 6.4 Vertiv™ Liebert® IntelliSlot™ Unity-DP Card A Liebert® Intellislot™ Unity-DP Card enables external communications with the Vertiv™ Liebert® STS2. The Liebert® Intellislot™ Unity-DP Card enables SNMP, BACnet IP, BACnet MSTP, Modbus TCP, Modbus RTU, YDN23, and Web management capability to the Liebert®...

  • Page 23: Transfer Inhibit

    6.7 Transfer Inhibit Transfer Inhibit prevents the Vertiv™ Liebert® STS2 from transferring under certain conditions. When a customer-supplied closed dry contact is provided, the Liebert® STS2 will not transfer and remain on its present source even if the source is no longer supplying power.
  • Page 24 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual This page intentionally left blank Proprietary and Confidential ©2025 Vertiv Group Corp. 6 Options...

  • Page 25: Installation Drawings

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 7 Installation Drawings Figure 7.1 Outline Drawing: 1200 Amp – 1850 Amp Vertiv™ Liebert® STS2 Item Description Item Description Removable Tophat Bottom View Optional Keylock Air Intake Area Do Not Block Air Filter...
  • Page 26 6. Color-Black gray Matte. 7. Open door to replace air filter, refer to user manual for filter specifications. Figure 7.2 Outline Drawing: 1200 Amp - 1850 Amp Vertiv™ Liebert® STS2 with Seismic Bracket Anchor Kit To Install the Brackets: The installation location must be a minimum of 6 in. (153 mm) from the rear of the unit for cooling air flow.
  • Page 27 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Figure 7.3 Main Components Area 1200-1800 A Chassis Vertiv™ Liebert® STS2 Item Description Item Description Customer Connection Area Source 1 Input Neutral If Equipped Source 1 Input A-Phase Output Neutral If Equipped Output A-Phase...
  • Page 28 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Figure 7.4 Electrical Connections 1200-1800 A Chassis Vertiv™ Liebert® STS2 Item Description Source 2 Input Source 1 Input Output Proprietary and Confidential ©2025 Vertiv Group Corp. 7 Installation Drawings...
  • Page 29 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Item Description Ground M6 Hex Insert NOTE: All Dimensions are in inch (mm). Figure 7.5 Control Connection Location Diagram Item Description Item Description Optional Communication Cards include IS-UNITY-DP card Low voltage wiring through (Max.
  • Page 30 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Figure 7.6 Control Wiring for Remote Source Selection Option  Notes to Figure: Customer provided normally open dry contacts. Rating 10 mA at 30 VDC. 2. Maximum cable length 500 ft. (152 m) with 16 AWG, 300V minimum, flexible stranded cable.
  • Page 31 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Figure 7.7 Control Wiring for the Programmable Relay Board Option Notes to Figure: Customer control wiring connection points are Terminal Blocks 1 through 12. 2. Programmable relay board option includes eight signal channels with one Form-C dry contact per channel. See table.
  • Page 32 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Figure 7.8 Control Wiring for the Input Contact Isolator Board Option Notes to Figure: Customer control wiring connection points are Terminals 1 through 16 see Table 7.2 below. 2. Customer provided, normally open, dry contacts for user alarm messages.
  • Page 33 Pin No. Input Contact Pin No. Figure 7.9 Control Wiring for the Vertiv™ Liebert® Intellislot™ Unity-DP Card Notes to Figure: Wire size and type: Standard category 5e cable with RJ-45 connector. Maximum length is 328 ft. (100 m). 2. Liebert integrated one-wire sensor cable or 2 m Cat 5e to modular one-wire sensor. Maximum length 65.6 ft. (20 3.
  • Page 34 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Figure 7.10 Control Wiring for the RS-232 Port Notes to Figure: RS-232 communication through DB9 connector. 2. Connector accessible with front door open. The cable must be removed before closing door. Proprietary and Confidential ©2025 Vertiv Group Corp.

  • Page 35: Introduction To Vertiv™ Liebert® Sts2 Operations

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 8 Introduction to Vertiv™ Liebert® STS2 Operations 8.1 System Description A Liebert® STS2 provides an automatic, seamless transfer between input power sources to an output load. The Liebert® STS2 monitors the input sources, to ensure each source is operating within set parameters, as well as ensure that each source is within acceptable tolerances for a transfer between sources to be completed.

  • Page 36: Reliability And Agency Requirements

    8.1.3 Factory Backup and Service Assistance Because improper installation can cause a system to fail, a Vertiv technician should inspect the unit to ensure that it is properly installed and that its operating parameters are properly configured. Once the Liebert® STS2 is properly installed, you, as the on-site operator, can easily monitor the unit’s operation utilizing the touchscreen.

  • Page 37: Mode Of Operation

    8.2.1 Normal (Preferred Source) Under normal operating conditions, the Vertiv™ Liebert® STS2 routes power from the preferred input source to the output load. The unit monitors the voltage current and phase of each source to ensure that both are operating within set tolerances, and that the alternate source is available, should a transfer be required.
  • Page 38 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Figure 8.1 Liebert® STS2 Touchscreen Display Touchscreen control buttons allow you to reset alarms, silence the audible alarm, review configurations, event and history logs, preferred source, startup and bypass procedures, and the help menu. Qualified personnel, with a password, can use these menus to configure parameters, select a preferred source, and do manual source transfers.

  • Page 39: Theory Of Operation

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 9 Theory of Operation 9.1 General Description The Vertiv™ Liebert® STS2 contains all the equipment necessary to prevent an interruption in power flow to the AC load, should your primary source fail. 9.1.1 Liebert® STS2 (Static Transfer Switch) The Liebert®...

  • Page 40: Emergency Transfer

    9.1.4 Emergency Transfer To ensure that power remains connected to the load, the Vertiv™ Liebert® STS2 automatically performs an emergency transfer from one input source to the other when an outage occurs on the existing source. The automatic transfer takes place if the other source’s voltage is within acceptable limits, and regardless of the phase difference between the two sources.

  • Page 41: On/Off Sequence

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Table 9.1 STS2 Current Range To Avoid SCR Open Alarms (continued) System Rating (Amps) RMS Current Present Threshold (Amps) % of Nominal Rating 37.56 4.70% 1000 37.56 3.76% 1200 37.56 3.13% 1250 37.56 3.00%...

  • Page 42: Detailed Component Description

    Operator Interface The Vertiv™ Liebert® STS2 Color Graphical Display unit contains a touchscreen color LCD to provide the operator interface to control and configure the operation of the unit and quickly diagnose problems. A password and an optional keylock, if installed, are provided for security.

  • Page 43: Scr's

    9.2.3 Logic Modules The logic contains three separate redundant logic modules. Each module contains the logic necessary to run the Vertiv™ Liebert® STS2 and control transfers and shunt trips under all circumstances, without any outside assistance, once set up and started properly.
  • Page 44 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual This page intentionally left blank Proprietary and Confidential ©2025 Vertiv Group Corp. 9 Theory of Operation...

  • Page 45: Operating Instructions For The Touchscreen Interface

    CAUTION: Before the unit is placed into service for the first time, after equipment relocation, or after the equipment has been de-energized for an extended period of time, a thorough equipment inspection and supervised startup by qualified personnel are strongly recommended. Contact your local Vertiv representative or Vertiv at 800-543-2378 to arrange for equipment inspection and startup.

  • Page 46: Maintenance Bypass

    10.2 Maintenance Bypass The Vertiv™ Liebert® STS2 may be equipped with two key-interlocked, bypass breakers, CB4 and CB5, to allow manual bypass of the switch electronics for either input source in the event of switch failure or for maintenance of the switch. Refer to the static transfer switch one-line diagram, Figure 5.1 on page 12 While operating on maintenance bypass with fuses F1 - F4 open,...
  • Page 47 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 10.2.1 Bypass Procedures for Source 1 To bypass the switch for Source 1: To bypass the Source 1 static transfer switch when Source 2 is presently active, you must first transfer to Source 1. See...
  • Page 48 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 10.2.2 Bypass Procedures for Source 2 To bypass the switch for Source 2: NOTE: To bypass the Source 2 static transfer switch when Source 1 is active, you must first transfer to Source 2. See...

  • Page 49: Enabling Remote Source Selection

    NOTE: If one source will be de-energized for an extended period (hours or days), set the unit to bypass mode for the remaining source. Without using bypass, if a failure occurs in the switch components for remaining source, the Vertiv™...
  • Page 50 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Figure 10.2 Source Transfer Screen To manually select the preferred source Verify that the input breakers CB1 and CB2 are closed. 2. Select SOURCE XFERS from the menu bar. The Select Preferred Source screen is displayed in the Event Display.

  • Page 51: Shutdown In Maintenance Bypass Mode

    10.5 Shutdown in Maintenance Bypass Mode When the Vertiv™ Liebert® STS2 is operating on bypass: Turn Off the load equipment per manufacturer’s recommendations. 2. Open the bypass switch (CB4 or CB5) to turn Off the static transfer switch output.
  • Page 52 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual This page intentionally left blank 10 Operating Instructions for the Proprietary and Confidential ©2025 Vertiv Group Corp. Touchscreen Interface...

  • Page 53: Alarm And Faults

    11 Alarm and Faults Alarms and faults are events that are triggered when the operation of the Vertiv™ Liebert® STS2 falls outside the defined parameters. These events can also be triggered by: user actions, such as changing configurations, clearing logs, etc.; failed components such as a fan failure, an SCR that is open or closed, etc.;...

  • Page 54: History Log

    Replay Rate: indicates how long it takes for the replay to play. Use the UP and DOWN buttons to set the time. • Status: the status of the Vertiv™ Liebert® STS2 at the point of the current frame in the replay. The History log has three statuses: Frozen, Not Frozen, and Retrieving Data.

  • Page 55: Alarm Notes

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 11.3 Alarm Notes The I-PK on Source 1 and I-PK on Source 2 alarms inhibit automatic transfer due to an overload or load fault. These alarms can be set for either auto or manual alarm reset.
  • Page 56 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Table 11.1 Event Messages (continued) Alarm Message Description/Cause Action PWR SPLY LOGIC FAIL A power supply module has failed. L, A, E OUT VOLT SENSE FAIL The output volt sense module failed. L, A, E S1 VOLT SENSE FAIL The Source 1 volt sense module failed.
  • Page 57 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Table 11.1 Event Messages (continued) Alarm Message Description/Cause Action S1 I-PEAK I-PK on Source 1. A, F, E S2 I-PEAK I-PK on Source 2. A, F, E SOURCES OUT OF SYNC Source 1 and Source 2 are out of synchronization.
  • Page 58 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual This page intentionally left blank Proprietary and Confidential ©2025 Vertiv Group Corp. 11 Alarm and Faults...

  • Page 59: Communication Interfaces

    NMS through SNMP/Web (HTTP). See Figure 7.9 on page 27 for more information on the Liebert® Intellislot™ Unity-DP Card. If you have questions about the card, refer to the User Guide, SL-52645, available at the Vertiv Website, www.Vertiv.com.

  • Page 60: Using The Rs-232 Port

    The RS-232 port is configured with a baud rate of 9600 with 8 data bits, 1 stop bit, no parity, and no hardware handshaking. 12.1.1 Connecting and Using a Terminal An RS-232 connection can be used to connect the Vertiv™ Liebert® STS2 to either a terminal or a PC running terminal emulation software. If you are unsure of the cable pin out, See Terminal Port Connections on page 89.

  • Page 61: Configuring The Vertiv™ Liebert® Sts2 Via The Terminal

    VER? Displays Displays firmware versions. 12.1.2 Configuring the Vertiv™ Liebert® STS2 via the Terminal The SPT command is used to configure the systems setpoints. The SPT syntax for the setpoints consists for four parameters: SPT [group] [item] [value] where the parameters are: •...
  • Page 62 Vertiv™ Liebert® STS2 via the Terminal on the previous page String Certain settings are represented by alphanumeric character strings, such as setting the System Model Number to Vertiv™ Liebert® STS2 Enumeration This type uses an indexed list to represent possible choices.
  • Page 63 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Table 12.3 Groups Settings and Values (continued) Group Item Description Value Type Value Notes Language Enumeration [Not supported at this time]. System Model Number String 14 character max. System ID Number String 8 character max.

  • Page 64: Setting Bitpacked Options With The Terminal

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Table 12.3 Groups Settings and Values (continued) Group Item Description Value Type Value Notes See section Setting Bitpacked Options with the Terminal Critical Option Enabling Bitpacked below. See section Setting Bitpacked Options with the Terminal...
  • Page 65 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual bit5: not used (set to 0). bit6: not used (set to 0). bit7: HasOpenCommsDigitalInputBrd. bit8: HasOpenCommsDigitalOutputBrd_1. bit9: HasOpenCommsDigitalOutputBrd_2. bit10: HasRemoteStatusPanelBrd_1. bit11: not used (set to 0). bit12: not used (set to 0). bit13: not used (set to 0).
  • Page 66 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual • 0 Option not installed or feature not enabled. Enabling or disabling the bits in each group creates a binary value for that group. For example, if the fourth bit in a group is set to 1, the group group’s binary value is 0001.

  • Page 67: Setting Event Masks With The Terminal

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual So your command to indicate that the Remote Source Selection and the Dual-Output Breaker are installed would be: SPT 2 6 0081 12.1.4 Setting Event Masks with the Terminal The event masks can be customized via a terminal. The command SPT4?<ENTER> displays all faults and alarms, along with their associated event masks.
  • Page 68 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual This page intentionally left blank Proprietary and Confidential ©2025 Vertiv Group Corp. 12 Communication Interfaces...

  • Page 69: Vertiv™ Liebert® Sts2 Touchscreen Display

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 13 Vertiv™ Liebert® STS2 Touchscreen Display The Liebert® STS2 can be configured with a Color Graphical LCD touchscreen that allows you to quickly check the status of the unit and identify problems. A touchscreen LCD is available through the front of the Liebert® STS2 This screen provides a graphical (Mimic) display of the switch’s operation, plus system information including system parameters, alarms and faults.

  • Page 70: Menu Overview

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 13.2 Menu Overview The touchscreen menu provides access to configuration settings and more device information. The CONFIG (Configuration) and LOGS menus provide multiple choices through pop-up menus. The SOURCE XFER menu selection allows you to select the preferred source. The other menu choices provide information in the display panel. The menu choices are discussed later in this manual.
  • Page 71 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Figure 13.3 Keyboard and Keypad Displays 13 Vertiv™ Liebert® STS2 Proprietary and Confidential ©2025 Vertiv Group Corp. Touchscreen Display...

  • Page 72: Security

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 13.2.1 Security Because the Vertiv™ Liebert® STS2 Color Graphical Display provides access to various configuration and monitoring choices, a password or key lockout switch may be used to protect access to certain changes, including: •...

  • Page 73: Mimic Display

    13.3 Mimic Display The Mimic display provides a color diagram of the operation of the Vertiv™ Liebert® STS2. This display imitates the power flow through the static transfer switch and indicates source status, breaker status, switch status, source voltage and current readings, output power measurements, and active alarm messages.

  • Page 74: System Ratings

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual • System Ratings: used to configure frequency, voltage and currents settings for the Vertiv™ Liebert® STS2. • Event Mask: allows you to configure system’s response for events. • User Settings: allows you to configure operations for the Liebert® STS2.

  • Page 75: User Settings

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Figure 13.5 Event Mask Dialog Box 13.7.3 User Settings The User Settings choice allows you to adjust the user-accessible switch settings. Access is limited to qualified personnel via system security. To access the User Settings dialog box: Select CONFIG.
  • Page 76 Source Set Points The Source 1/2 Set Points allows you to configure trigger points for each input source (1 or 2) for the Vertiv™ Liebert® STS2 via a keypad dialog or HI/LO dialog box. The source numbers do not designate the source as the preferred or alternate source.
  • Page 77 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual • Slow UV Setting (%): if the voltage remains this set percentage below the nominal voltage for the period of the slow detection delay, the Liebert® STS2 transfers from the current source to the opposite source.
  • Page 78 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Table 13.1 Setpoint Parameters Button Range Default Comments Fast UV Setting (%) -10% to -30% of Nominal voltage rating -20% Set in increments of 1%. Slow UV Setting (%) -5% to -20% -10% Set in increments of 1%.
  • Page 79 Select NO to disable the automatic transfer. The setting requires transfers be done manually. 13. Set the AUTO RESTART ENABLE choice. This setting determines whether the Vertiv™ Liebert® STS2 can be started automatically when power is restored after it has been lost.

  • Page 80: System Settings

    2. Select SYSTEM SETTINGS from the Config menu. 13.8 Comm Options The Comm Options dialog box allows you to configure the communications settings for the Vertiv™ Liebert® STS2: • Select COMM OPTIONS from the System Settings Menu. (If needed, See...

  • Page 81: Configuring The Input Contact Isolator Settings

    The Input Contact Isolator (ICI) is an optional, eight-channel input board for up to eight external user alarm or message inputs to be routed to the Vertiv™ Liebert® STS2's alarm network. If the Transfer Inhibit option is supplied, the ICI will accommodate up to seven external user alarm or message inputs.
  • Page 82 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual The delay allows you to set the number of seconds which a condition needs to persist to trigger an alarm. These input alarms can also be configured to activate a programmable relay output, which is discussed in...

  • Page 83: Configuring The Programmable Relay Board Settings

    13.8.2 Configuring the Programmable Relay Board Settings The Vertiv™ Liebert® STS2 can contain up to two Programmable Relay Boards (PRB) that can trigger an external device when an event occurs in the Liebert® STS2. For example, if Source 1 fails, an external light flashes.
  • Page 84 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Once configured, the Vertiv™ Liebert® STS2 continuously checks the status of the items defined for each contact and updates the state of the relay. To configure your programmable relay boards for user defined settings: Select PROG.

  • Page 85: Configuring The Vertiv™ Liebert® Intellislot™ Unity-Dp Card

    13.8.3 Configuring the Vertiv™ Liebert® Intellislot™ Unity-DP Card An optional Liebert® Intellislot™ Unity-DP Card can be installed in the Vertiv™ Liebert® STS2 to provide Ethernet connectivity via an RJ-45 port. Ethernet cabling is the responsibility of the customer. Category 5 cabling is required.
  • Page 86 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Figure 13.11 System Options Dual Output Breaker This selection is set at the factory. The choice is set to YES to enable both output breakers (CB3 and CB3A) when two are installed in the unit. If only one output breaker (CB3) is installed, the setting is set to NO.

  • Page 87: System Id

    13.10 System ID Most of the settings for System ID are set by Vertiv either at the factory or when the unit is installed. Order No., System Tag No., System ID No., and Model No. are the numbers used to identify and track the system.

  • Page 88: History Log

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Figure 13.12 Event Log To use the Event Log: Select LOGS from the menu bar to open the Logs menu. 2. Select EVENT LOG from the menu. 3. Use the UP and DOWN buttons to scroll through the event list.

  • Page 89: Source Transfers

    To switch the primary source, refer to the instructions in Manual Transfer/Preferred Source Selection on page 43 13.13 Startup Procedure You can access instructions for starting the Vertiv™ Liebert® STS2 from the menu bar. • From the menu bar, select STARTUP PROC. These instructions are also provided on Normal System Startup on page 39 for Color Graphical display units.

  • Page 90: Bypass Procedure

    Event Message Help Text on page 91. 13.16 Logo The Logo menu choice shows the Vertiv™ logo in the display panel. 13.17 Cleaning the LCD Touchscreen If the touchscreen requires cleaning, use a pre-moistened towelette designed for cleaning computer monitors, or dampen a soft, non-abrasive cloth with a very mild cleaning solution.

  • Page 91: Specifications

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 14 Specifications This section provides the specifications for the Vertiv™ Liebert® STS2. 14.1 System Configuration The Liebert® STS2 can be set in several different configurations, according to the model and location. The configuration is set at the factory and does not need to be changed by the customer.

  • Page 92: System Current Ratings

    *Actual duration may be shorter depending on the upstream over current protection devices. 14.1.6 Input Surge Suppression The Vertiv™ Liebert® STS2 is equipped with transient voltage surge suppression on each input for maximum surge suppression. The surge suppression is capable of protecting the Liebert® STS2 from operating outside of tolerances due to surges as defined by IEC 6100-4-5 (1.2/50uS surge, 2kV CM and 1kV DM) as required under ANSI C62.41 Category B3 (6kV).

  • Page 93: Response Time

    14.1.7 Response Time A dual level fast/slow transfer threshold is used for under voltage detection to allow the Vertiv™ Liebert® STS2 to be compatible with UPSs and generators. The voltage thresholds and the slow transfer delay time is user-adjustable. The fast transfer delay time is less than 4 ms.

  • Page 94: Access

    14.2.4 Access The Vertiv™ Liebert® STS2 is designed so all repairs and maintenance can be done from the front or top of the unit. All components that may need repair or replacement during routine field maintenance are safely accessed with the units in bypass without removing power from the unit.

  • Page 95: Color Graphical Display

    Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual 14.2.7 Color Graphical Display The display is located in the front of the unit. Front panel display is either an LCD touchscreen display for monitoring and configuring the unit. See Figure 8.1 on page 32for a drawing of the touchscreen display.

  • Page 96: Interface Parameters

    Local Echo 14.2.11 Maintenance Bypass The Vertiv™ Liebert® STS2 is configured to allow the unit’s electronics to be bypassed to either input source for maintenance without interruption of power to the load. The Liebert® STS2 is furnished with key-interlocked maintenance bypass breakers to configure the bypass.

  • Page 97: Event Message Help Text

    Press SILENCE on the touchscreen to turn Off the audible alarm, if so configured. If you are accessing the Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm.
  • Page 98 This event was also written to the Event Log, if so configured. PRIMARY FAN FAIL Primary Fan Failure. One of the primary cooling fans for the Vertiv™ Liebert® STS2 has failed. The alternate fans are now running. The alternate fans are not monitored.
  • Page 99 Press SILENCE on the touchscreen to turn Off the audible alarm, if so configured. If you are accessing the Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm.
  • Page 100 Press SILENCE on the touchscreen to turn Off the audible alarm, if so configured. If you are accessing the Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm.
  • Page 101 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm. Contact Vertiv at 800-543-2378. This event was written to the Event Log, if so configured.
  • Page 102 Press SILENCE on the touchscreen to turn Off the audible alarm, if so configured. If you are accessing the Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm.
  • Page 103 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm. Contact Vertiv at 800-543-2378. This event was written to the Event Log, if so configured.
  • Page 104 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual If configured to be a latching alarm, press RESET on the display. If you are accessing the unit from a terminal, type CA and press RETURN on your keyboard. Proprietary and Confidential ©2025 Vertiv Group Corp.
  • Page 105 A standard furnace filter can be used. Press SILENCE on the touchscreen to turn Off the audible alarm, if so configured. If you are accessing the Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm. This event was written to the Event Log, if so configured.
  • Page 106 Fail alarm was also issued and source transfer has been inhibited. The load of the Vertiv™ Liebert® STS2 has been transferred to Source 1. Press SILENCE on the touchscreen to turn Off the audible alarm, if so configured. If you are accessing the Proprietary and Confidential ©2025 Vertiv Group Corp.
  • Page 107 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm. The alarm is latched and must be reset after the voltage returns to the nominal voltage. If the Reset option is not configured for AUTO (automatic reset), then the reset action must be done manually.
  • Page 108 S1 OVERCURRENT Source 1 Overcurrent. Vertiv™ Liebert® STS2 is running on Source 1 and an overload condition has occurred on one or more phases. Note: The overload setpoint is a single fixed number--101%. An overload condition is detected when the measured load current is equal to or greater than the setpoint.
  • Page 109 CA and press RETURN on your keyboard. LOAD ON ALT SOURCE Vertiv™ Liebert® STS2 load on the alternate source. The static transfer switch is running on the alternate power source. Check the Event Log to determine the reason for the transfer from the preferred source.
  • Page 110 Press SILENCE on the touchscreen to turn Off the audible alarm, if so configured. If you are accessing the Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm.
  • Page 111 Press SILENCE on the touchscreen to turn Off the audible alarm, if so configured. If you are accessing the Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm.
  • Page 112 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual This event was written to the Event Log, if so configured. If configured to be a latching alarm, press RESET on the display. If you are accessing the unit from a terminal, type CA and press RETURN on your keyboard.
  • Page 113 Press SILENCE on the touchscreen to turn Off the audible alarm, if so configured. If you are accessing the Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm.
  • Page 114 Press SILENCE on the touchscreen to turn Off the audible alarm, if so configured. If you are accessing the Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm.
  • Page 115 Press SILENCE on the touchscreen to turn Off the audible alarm, if so configured. If you are accessing the Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm.
  • Page 116 Press SILENCE on the touchscreen to turn Off the audible alarm, if so configured. If you are accessing the Vertiv™ Liebert® STS2 system from a terminal, type SH and press RETURN on your keyboard to turn Off the audible alarm.
  • Page 117 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual If configured to be a latching alarm, press RESET on the display. If you are accessing the unit from a terminal, type CA and press RETURN on your keyboard. 15 Event Message Help Text...
  • Page 118 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual This page intentionally left blank Proprietary and Confidential ©2025 Vertiv Group Corp. 15 Event Message Help Text...

  • Page 119: Maintenance

    STS2. Minimal periodic maintenance of the Vertiv™ Liebert® STS2 is required. As with all electrical distribution components, the system should be regularly inspected for electrical connection integrity, signs of excessive temperatures, dirt accumulation, and proper system operation.
  • Page 120 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual This page intentionally left blank Proprietary and Confidential ©2025 Vertiv Group Corp. 16 Maintenance...
  • Page 121 Vertiv™ Liebert® STS2 1200A-1850A Chassis User Manual...
  • Page 122 Vertiv.com | Vertiv Headquarters, 505 N Cleveland Ave, Westerville, OH 43082 USA ©2025 Vertiv Group Corp. All rights reserved. Vertiv™ and the Vertiv logo are trademarks or registered trademarks of Vertiv Group Corp. All other names and logos referred to are trade names, trademarks or registered trademarks of their respective owners. While every precaution has been taken to ensure accuracy and completeness here, Vertiv Group Corp.

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