Plasma Power Supply
24 809970 Field Service Bulletin XPR300
Replace the coolant thermistor
See Coolant system on page 122 for location and part number.
1. Complete the following procedures:
a. Remove the power from the cutting system.
b. See Remove the right-side (liquid-cooling-side) panel on page 60.
c. To make removing the thermistor easier, you can remove the top panel. See Remove the top 
panel on page 63.
Keep all nuts and screws that you remove.
2. Disconnect the thermistor 
wire connector (J5).
3. Remove the wires from the 
wire clip.
4. Carefully remove the 
copper clip from the pipe.
5. Use the new copper clip to 
install the coolant 
thermistor onto the straight 
part of the pipe with the 
wires going toward the 
heat-exchanger panel.
Make sure that 
the copper clip 
fits tightly around the pipe.
Make sure that the concave side of the coolant 
thermistor is toward the pipe.
Do not put the coolant thermistor on the fittings of the 
heat-exchanger assembly.
6. Connect the thermistor wire connector (J5).
7. Install the liquid-cooling side panel.
8. Use the XPR web interface to make sure that there are no coolant temperature errors.
For more information on the XPR web interface, see the Connect for 
Communication in the XPR300 Instruction Manual (809480).