Forced Cold Start Procedure

Document created by paolalab Employee on Oct 21, 2020Last modified by paolalab Employee on Oct 30, 2020
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Agilent Support Insights


This Information Applies To: All Agilent HPLC modules (except hosted modules).



If a module does not initialize correctly or it is not recognized by the software it is recommended to call our Remote Support Engineers to troubleshoot the issue. You may be asked to follow the cold start procedure below to recover the correct functionality of the module. A forced cold start can be used to bring the module into a defined mode with default parameter settings.


Before starting:

  • Save your methods and data before executing a forced cold start. A forced cold start erases all methods and data stored in the non-volatile memory of the module, i.e a non saved state.
    Exceptions are calibration settings, diagnosis and repair log books which will not be erased.


Do not use a pencil or a fragile tool to move the switches to avoid breaking it inside the module. We recommend you to use a screwdriver or a pen.


Steps to follow:

  • Switch OFF the modules.
  • Disconnect the cables that connect the troubled module to the others.
  • Take note of the current configuration of the switches which are on the back of the module inside the CONFIG slot (Figure 1). This is important, because after the procedure you will have to move the switches back to that original configuration. Your module might have 2, 6 or 8 switches depending on the model. The 6-switch configuration is for all Infinity II Series modules except the Hosted modules that use a 2-switch configuration (Multicolumn Thermostat, Flexible Cube, UIB II, and 1290 Infinity Valve Drive), while the 8-switch configuration is for 1100 and 1200 Series instruments.


config switches position
config 2 switches config 6 switches config 8 switches

Figure 1. Location of Configuration Switch (CONFIG) and different type of Switches of HPLC modules.


  • Change the switches configuration according to Table 1 below.


2 switches0 1
6 switches1 0 0 0 0 1
8 switches1 1 0 0 0 0 0 1

Table 1: Switches' configuration for a forced cold start. 1 means up, 0 means down.



  • Switch ON the instrument and wait 3 minutes until the initialization is completed.
  • Switch OFF the instrument.
  • Place the switches in their original position.
  • Reconnect all the cables and switch ON all the modules in the stack.


Special consideration: 

The instrument will always revert to the default state after a cold start. This is especially important for plate types and the metering head size in autosamplers. For example, the 900 µL analytical head upgrade will not be recognized. It must be set again in the software (the same as during initial installation). The sampler will default to the standard 100 µL head.


Learn more on how to operate your Agilent LC System:

LC User manual library on


Keywords: stuck autosampler, LC error, memory, connection, non-volatile memory, board LAN, boot main, default settings