Long-Term Chamber Thermistor Upgrade or Replacement Instructions

The 8100-908 is a replacement/upgrade for the thermistor assembly in the 8100-101 Long-Term Chamber. The 8100-908 can be field installed; the upgrade requires approximately 15-20 minutes to complete.

Tools required: Philips head screwdriver, 11/16” open end wrench, and a knife or pair of cutters.

Follow these steps to replace the thermistor assembly:

1. Manually open the chamber, using the Manual Controls function in software, until it reaches a vertical position at the apex of its movement. This will allow you to remove the white chamber “bowl” in a later step.
2. Remove the pressure vent from the top of the chamber. In many cases you can simply twist the vent assembly counterclockwise with your hands to remove; if not, use the 11/16” open end wrench to loosen the nut at the base of the vent assembly.
3. 
3. Remove the 4 screws from the top mounting plate assembly, underneath the pressure vent.
4. 
4. Remove the 2 screws at the edge of the top mounting plate assembly that secure the air tubing assembly.
5. 
6. The chamber “bowl” can now be moved away from the top plate assembly to access the old spacer/thermistor assembly.
7. 
5. Remove the 4 screws from the underside of the chamber “bowl”, and remove the attached mounting plate. The old spacer/thermistor assembly can now be moved away from the top of the chamber “bowl”.
6. Cut the air tubing off as close to the hose barbs as possible. Unscrew the collar from the thermistor cable between the two hose barbs. Discard the old spacer/thermistor assembly.
7. 
7. Insert the air tubing over the two hose barbs on the 8100-908; it does not matter which tube is attached to either barb. Reattach the thermistor cable collar.
8. 
8. Make sure the O-ring is in place in the new 8100-908 assembly. Insert the assembly through the holes in the top of the chamber “bowl”. Replace the mounting plate removed in Step 5 above and secure with 4 screws.
9. 
9. Move the chamber “bowl” back under the top mounting plate assembly, and align the holes in the 8100-908 assembly with the 4 screw holes in the top mounting plate assembly. Replace the 4 screws on the top mounting plate that were removed in Step 3 above.
10. Reattach the air tubing assembly at the edge of the top mounting plate assembly.
11. Make sure the O-ring is in place in the nut at the base of the pressure vent support tube. Reattach the pressure vent assembly. The assembly is complete.