Help firing an older Ceramichrome Autofire with Kiln Sitter

[bwhittle]

This summer I purchased an older kiln at an estate sale. I’ve attached photos of the controls, and the model number. I’ve tried to fire to cone 04 a few times for a test firing, but so far the kiln sitter shuts off around 5 hours, and the self supporting cone is barely bent. 
The top dial, I’m assuming is the temp, and the second a timer. 
does anyone have any suggestions on a firing schedule? So far I’ve tried 2nd knob ON — 1st knob 4 hours at low, the switched to medium, and then the sitter shuts off after about an hour at medium. 
 

any advice would be so greatly appreciated!!!! Thank you!! 
Bridget

[neilestrick]

Welcome to the forum!

Is the sitter shutting it off because the timer gets to zero, or because the weight is dropping and kicking out the power button? If it's getting to zero, then you just need to set it to more time until you figure out how long a firing is actually going to take. The sitter timer is just a countdown timer- it has nothing to do with how long the kiln will take to get to temperature. When it hits zero it turns it off, regardless of how hot the kiln is. If the weight is dropping too early, then you need to adjust the sitter. Manual attached.

Kiln-Sitter Models P & K Operating Manual.pdf

[bwhittle]

Thank you so much! Yes the weight was dropping early. I set the sitter time to 13 hours, but it dropped very early in the firing. Thank you so much for the link! Very helpful!!! 

[neilestrick]

The cone in the sitter (small cone or bar only, not a large cone ) should be bent to 90 degrees. Adjust accordingly. If that doesn't match up with a shelf cone then try the next cone up in the sitter.