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August 16, 2017

Resetting the Thermal Safety Switch / Priming the TCS Pump


The circulator is not turning on due to thermal switch reset. This occurs when the TCS pump is not primed properly.


Service Engineer or person performing this service must have proper training in servicing the instrument.

Resetting the Thermal Safety Switch

1. Turn off the TCS and unplug from the AC outlet prior to resetting the thermal switch.

Note: Make sure that the TCS has had time to cool down prior to resetting the thermal safety switch. This can take up to 10 to 20 minutes.

2. On the back of the TCS there is a small access hole where the thermal safety switch is located (As shown below). Using a non-metallic tool or the end of a pen or pencil, reset the thermal safety switch by depressing the button. You should feel or hear a click indicating that the switch has been reset.

3. Once the thermal safety switch has been reset, make sure the TCS has been properly primed or the thermal safety switch will trip again. Please see Priming the TCS Pump steps below. Turn on the unit and enable the heater.

Note: Information about resetting the thermal safety switch can be found on page 3-14 in the 2100C Operation Manual.  Information about priming the pump can be found on page 2-6 in the 2100C Operation Manual and on page 2-8 of the EVO 6300 Operation Manual.

Priming the TCS Pump

1. Attach a 24 inches (61 cm) long x ½ inch (13mm) ID drain tubing to drain valve.

2. Raise the drain tubing to vertical position as shown. Drain valve should be tilted up.

3. Cover the end of the tubing with your thumb and open the drain valve. Slowly lower the tubing while slowly opening the end of the tubing allowing water to fill up as much of the tubing. Once filled, close again the end of the tubing with your thumb and raise the tubing. Uncover the end of tubing to force water in to the pump inlet. Perform this step at least two to three times. Turn on the TCS circulator and observe that air has been purged from the pump indicating that the pump was primed correctly. If it does not, repeat step 2 and 3 until all the air is purged from the pump

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