1) Review profile plot. If ramp rate to overtemp does not look realistic (there is a vertical upshoot) then possible bad RTD or bad RTD connection.
2) There is a software lockup.
3) Review profile plot. If ramp rate to overtemp looks realistic, then it may be bad top heater control (main PCBA).
Possible Solutions (corresponding to the Causes #):
1) Tighten the female connectors for the top heater RTD (sensor and safety). Replace heater head assemly if necessary (APR-HHA). Replacement instructions: APR-HHA Replace.pdf
2) Close the software and reboot the computer. Disable all the power saving features in Windows (do not want to power down while running the machine).
3) Replace the main PCBA only if overtemp validated as being realistic (APR-XL-LCPCB). Replacement instructions: APR-XL-LCPCB Replacement Instructions.pdf
If you need instructions on how to replace or check any of these parts, please contact our APR Support Team.