What does “open” mean when displayed on a Lachat heater controller?
"Open" message on heater controller
Open will be displayed if the thermocouple is not plugged in. The plug for the thermocouple (Catalog Number/Order Code 85268) is yellow on the Lachat heater module assembly (Catalog Number/Order code A85x32) for the QC8500. If this is properly plugged in and another channel with heater is available, one can swap the heater block with attached thermocouple to see if the problem moves with the thermocouple. If the problem does not move with the thermocouple the issue is likely with the heater controller. For issues with the heater controller the heater module assembly should be repaired or replaced.