Why Are the Pen Traces Erratic?
Causes and Troubleshooting:
Is the Pen Arm screw secure? If not, tighten until it is properly secured.
Is the Chart Recorder sitting on or mounted to a surface prone to vibration? If so, consider relocating the recorder.
For Temperature only units, try removing the unit from the application and placing it in an isolated, low air flow environment like a zip lock freezer bag or desk drawer. If the pen traces straighten out, the traces may have actually been caused by the changes in your application.