Close-up of a sophisticated, modular machine component setup with metal parts, connectors, and tubing arranged on a mounting plate. The machine is illuminated by blue lighting, highlighting its intricate mechanical elements.

Scientific Product Troubleshooting

T257P and Rack Mount Chiller Troubleshooting

1. My ThermoTek chiller is fluctuating rapidly around the set point.

When a chiller fluctuates quickly around the set point, this is typically a low fluid flow issue. Many times this is due to contamination in the chiller, specifically inside the quick disconnect fittings on the chiller.

More than likely, there is particulate contamination collecting at the supply-side quick disconnect fitting on the chiller. The supply-side fitting is the top fitting on T257P chiller and the bottom fitting on a Rack-Mounted chiller. This restriction is causing low fluid flow through the fittings and chiller, causing the instability.

Empty your chiller of fluid and remove and clean (or replace) both fluid fittings on the chiller, then reassemble and retest. Cleaning or replacing the fluid fittings is an important step. The connectors on the side of the unit that your system plugs into are removable. If you use a wrench or pliers, they will unscrew from a fitting inside the chiller. Remove them over a sink or bucket, as the fluid will pour out. Clean the inside of that connector and pour a liter or so of distilled water into the reservoir to flush any additional material out. When you reinstall the fittings, ensure the threads are dry then use clear silicone sealant on the threads to prevent leaks. The flow should return to normal and the temperature should stabilize.

2. My ThermoTek chiller is no longer cooling

Please confirm that your chiller reservoir is full, the pump is working and fluid is flowing back through the chiller when in Cooling mode. If the pump is not working or if you cannot tell if the pump is working, refer to Question 3 below.

If you have confirmed that fluid is flowing through the chiller, check the Control Mode of the chiller (T257P only) to ensure the setting is the default HIFLOW setting. The Control Mode can be found by cycling through the main menu when the chiller is powered on and in Standby mode.
Connect a short loop-back hose (~12 inches long) from the inlet to the outlet of the chiller.

Power ON the chiller, Press the START button and set the chiller to 15°C. You may need to Start and Stop several times to clear any air from the connected hose. Open the reservoir cap to confirm turbulence in the water.
Confirm fluid is flowing through the 12” hose set and allow several minutes to stabilize to 15°C. If the chiller temperature does begin cooling soon after you can check the MONITOR screens of the chiller to review operational temperatures.

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Monitor Screen:

While in Cooling Mode, if the MANF TEMP is not dropping, or is higher than the SET TEMP, then your chiller is not cooling and must be returned for repair.
While In Cooling Mode, if the MANF TEMP is lower than the SET TEMP, but the SUPLY TEMP (Supply Temp) is higher than SET TEMP, then there is no water flow occurring through the chiller. Refer to Question 3 below.

3. My ThermoTek chiller is no longer pumping fluid

Many times when a chiller is no longer pumping fluid this can be due to air lodged in the pump, preventing fluid from pumping correctly. To test your chiller function and remove any air from your pump, run the following setup and test.

Disconnect the chiller from any connected laser/x-ray system.
Remove the reservoir cap.
Connect a hose and funnel to the Return port of your ThermoTek chiller. (Note: the Return port on the T257P model is the Lower port; the Return port on any Rack-Mounted chiller is the Upper port.)

Add fluid into the funnel (or tube) which will feed back through the thermoelectric engine and pump all the way to the reservoir (Note: The funnel picture below is showing our Rack Mount chillers). Pour fluid into the funnel (or tube) until the reservoir is completely full.

Disconnect the hose and funnel and now connect a short loop-back hose (~12 inches long) from the inlet to the outlet of the chiller.

Power ON the chiller and press START button and set the chiller to 15°C. You may have to START several times to fully remove any air from the pump and connected hose.
Confirm fluid is flowing through the 12” hose set and allow several minutes to stability to 15°C.

4. My T257P chiller is cooling very slowly

Check the Control Mode of the chiller (T257P only) to ensure the setting is the default HIFLOW setting. If the Control Mode is set to LOFLOW (Low Flow), change it back to the default HIFLOW. The Control Mode can be found by cycling through the main menu when the chiller is powered on and in Standby mode.

5. What fluids are acceptable to use in my ThermoTek chiller?

Cooling Fluid options:

100% distilled water (replace monthly to prevent biological growth)
90% distilled water/10% isopropyl alcohol (prevents bacterial growth; replace every 90 days)
80% distilled water and 20% corrosion inhibited Glycol (operation down to -5°C)
Optishield
Koolance 702
CoolFlow DTX
Dow Frost Prestone 5/150
PrestoneLowTox Antifreeze approved for aluminum exposure

NOT Acceptable Cooling Fluid:

Deionized (DI) Water
Polyalphaolefin (PAO)
Lauda Aqua 90
OptiCool-H
Fluorinert
Mineral Oil (oranytypeofoil)

6. My reservoir is full but my chiller shows a Low Coolant Level alarm

The low coolant level alarm is typically triggered by the float switch inside the reservoir. If the chiller has been emptied of fluid for a period of time, microdeposits can form between the clear plastic float and the base of the shaft causing the float to be lightly adhered to the bottom of the shaft. If this is the case, you can gently tap the plastic float which will break it free from the microdeposits that were holding it in place. This should allow your chiller to begin working normally again.

If the float is already freely floating on the shaft then likely the entire float assembly, or control board that it plugs into may need replacing. Contact ThermoTek if you would like to arrange for an RMA to return your chiller for a repair quotation.