THORLABS LK220 User manual

LK220
Thermoelectric
Liquid Chiller
User Guide

Liquid Chiller
Table of Contents
Chapter 1Safety..............................................................................................................................1
Chapter 2Overview.........................................................................................................................2
Chapter 3Getting Started...............................................................................................................3
3.1.Shipping List.............................................................................................................. 3
3.2.Front & Back Panels ................................................................................................. 4
Chapter 4Operation........................................................................................................................5
4.1.Starting the Device.................................................................................................... 5
4.2.Front Panel Operation............................................................................................... 7
4.2.1.Quick Operation ............................................................................................................. 7
4.2.2.SetTemp ......................................................................................................................... 7
4.2.3.Menu .............................................................................................................................. 8
4.2.4.Status Display ................................................................................................................ 9
4.3.I/O................................................................................................................................ 9
4.4.LED Indicator ........................................................................................................... 10
4.5.Connecting an External Sensor ............................................................................. 10
4.6.Software Operation ................................................................................................. 11
4.7.Dust Filter................................................................................................................. 11
Chapter 5Command Line Operation..........................................................................................12
5.1.Description of Commands...................................................................................... 14
Chapter 6Maintenance.................................................................................................................19
6.1.Fuse Replacement................................................................................................... 19
6.2.Draining The Reservoir........................................................................................... 19
Chapter 7Specifications..............................................................................................................20
Chapter 8Mechanical Drawings..................................................................................................22
Chapter 9Certification and Compliance....................................................................................23
Chapter 10Regulatory....................................................................................................................25
Chapter 11Thorlabs Worldwide Contacts...................................................................................26

Liquid Chiller
Rev A, December 6, 2019 Page 1
Chapter 1 Safety
The device comes with a switching power supply compatible with voltages from 100 to 240 VAC. There is no
need to change the fuse when selecting your regional voltage. If the user needs to change the fuse located
below the AC plug on the back of the unit, see section 6.1.
SHOCK WARNING
High voltage inside. To avoid electrical shock, before powering unit, make sure that the
protective conductor of the 3-conductor power cord is correctly connected to the protective
earth contact of the socket outlet. Improper grounding can cause electric shock resulting in
severe injury or even death. Do not operate without cover installed.
WARNING
This unit must not be operated in explosive environments.
WARNING
Always power off the unit before opening the housing.
CAUTION
Never disassemble the chiller as irreparable damage may occur.
CAUTION
Do not operate the chiller in ambient temperatures of 40 ºC or higher.
CAUTION
Do not operate the chiller within 2 ºC of the coolant’s freezing point.
CAUTION
Do not store the chiller over 60 °C.
CAUTION
Do not use alcohol (methanol, ethanol or isopropanol) based coolants.
CAUTION
Do not ship the chiller with coolant inside the unit as freezing temperatures may be encountered
which would damage the unit. Always pump all coolant out of the chiller prior to shipping.

Liquid Chiller
Page 2 CTN014239-D02
Chapter 2 Overview
The LK220 is an air-cooled, recirculating liquid chiller based on thermoelectric elements (TECs) that provides
up to 1.2 bar of pumping capability. The bi-polar operation of the TECs allows the LK220 to be used for cooling
or heating applications. This liquid chiller has a maximum heat pump capability of 200 W when set to the ambient
temperature and a temperature control stability of ±0.1 °C. The temperature can be set between -5 °C and
45 °C using the front panel controls or the software GUI when the unit is connected to a PC via the included
USB cable.
For easy hose installation or removal, the LK220 features valved quick-connections. Two valved quick-
connection fittings and 5 meters of hose with 4 mm inner diameter are included in the package.
The LK220 is designed to be used with the CDTX Coolflow DTX Refrigerant Antifreeze, which is available on
the Thorlabs website. This liquid chiller is compatible with most ethylene glycol-based antifreeze or coolant.
Water can also be used as an alternative coolant, however, the cooling performance is reduced. Please note
that a funnel and a siphon pump are included to help transfer coolant into the chiller.
To measure the outlet coolant temperature, the LK220 is equipped with an internal thermistor sensor. The
LK220 also features an external sensor port for more precise temperature control, which is compatible with
Thorlabs' TSP-TH temperature probe (not included) or other third party thermistors.

Liquid Chiller
Rev A, December 6, 2019 Page 3
Chapter 3 Getting Started
3.1. Shipping List
The package contains the following items:
 1 Chiller
 1 Power Cord
 1 USB Cable
 5 Meters of 4.3 mm (0.17”) Inner Diameter Hose
 1 Siphon Pump
 1 Funnel
 2 CPC® Valved Quick-connection Fittings for 4.3 mm (0.17”) Inner Diameter Hose
 1 Flash Drive Containing the Operation Software and Manual

Liquid Chiller
Page 4 CTN014239-D02
3.2. Front & Back Panels
Figure 1 Front and Back Panels of LK220
 F1. Secondary Power Switch
 F2. SMA Port for Analog IN: 0 V to 5 V
 F3. 2.5 mm Stereo Jack for External Thermistor
 F4. LCD Screen
 F5. Knob for Adjustment and Confirmination / LED Indicator
 F6. SMA Port for Trigger IN: 5 V CMOS
 F7. BNC Port for Interlock: 0 V to 5 V
 F8. BNC Port for Monitor: 0 V to 5 V
 F9. USB Port
 F10. Airflow Inlet
 B1. AC Power Inlet / Fuse Drawer / Main Power Switch
 B2. Airflow Output
 B3. 1/4" Hose Valved Coupling Insert for Coolant Supply
 B4. 1/4" Hose Valved Coupling Insert for Coolant Return
F2
F1
F6
F7
F5 B1
F4
F8
F3
F10
F9
B2
B3
B4

Liquid Chiller
Rev A, December 6, 2019 Page 5
Chapter 4 Operation
4.1. Starting the Device
Connect the hose to the female quick-connection fittings provided in the package. Then, connect the hose to
the coolant in/out port on the back panel of the chiller. Connect the other side of the hoses to the thermal load.
Figure 2 Ferruleless Compression Fitting for Easy Connection with Tubing
Figure 3 Connecting Hoses to the LK220

Liquid Chiller
Page 6 CTN014239-D02
Open the hatch on top of the chiller and remove the plastic cap. Fill the reservoir with coolant, using the included
funnel for help if necessary. If moving coolant from a large container, we strongly recommend using the included
siphon pump. Please note that this device is safe to operate even if small spills occur or the reservoir overflows.
Figure 4 Removing the Plastic Cap (Top) and Filling the Reservoir (Bottom)
Toggle the rocker switch (B1 in Figure 1) on the back panel to “I” to power on the device. Press the secondary
power switch (F1 in Figure 1) on the front panel to enable the system.
Leave the reservoir open and set the target temperature to room temperature (see section 4.2 for details). Start
running the chiller. The pump will start, filling the tubes and heat load with coolant, and the air remaining inside
will be released to the atmosphere at the open reservoir. If the coolant level is low, an alarm will start. Fill the
reservoir with more coolant and press the knob to reset the warning.
Figure 5 Set Target to Room Temperature and Run LK220
Once the hoses, heat load, and the reservoir are filled, put the cap back on the reservoir, close the hatch, and
start regular operation.

Liquid Chiller
Rev A, December 6, 2019 Page 7
4.2. Front Panel Operation
Turn the knob to move the cursor on the screen, and press to confirm/select. The device status is displayed on
the title bar (see Section 4.2.4).
4.2.1. Quick Operation
Set the target temperature by selecting Target and turning the knob clockwise or counterclockwise to increase
or decrease the temperature, respectively. Press the knob to confirm the temperature value. Select the
Run/Stop option to enable the device.
Figure 6 Quick Operation to Run LK220 by Panel Control
4.2.2. SetTemp
Select the SetTemp button to enter the set temperature screen; the target temperature and temperature window
can be set here. The temperature control window defines the allowed temperature shift of the device. Please
note that a warning message appears when the difference between the actual and target temperature if larger
than the temperature window. However, the chiller will continue to run.
Figure 7 SetTemp Menu Accessed with Panel Control