To calibrate instrument, bring solder to operating temperature and allow sufficient time to stabilize: check that thermocouple is properly in well, then proceed as follows:

1. If switching does not occur within proper span (approx. 5 degrees F above and below zero) then the indicator needle must be adjusted.
   
2. Remove unit from console by unscrewing removal screw and pulling instrument out of casing. Locate needle adjust screw and rotate needle in appropriate direction. Replace in casing and check results: repeat until desired accuracy is attained.
   
3. To calibrate temperature, place an accurate thermometer in the solder wave and compare set point temperature with measured temperature. If there is a significant difference the R5 potentiometer must be adjusted.
   
4. Rotate set point knob to measured temperature then remove unit from casing and rotate R5 screw clockwise to decrease temperature or counterwise to increase. Replace in casing and check results; repeat until desired accuracy is attained.
   
5. Should unit fail to operate properly, check for defective thermocouple; check wiring if necessary.