InstroTek, Inc.

The furnace is not heating

  • If the temperature is below 50F (10C), take a match/cigarette lighter, and apply the flame directly to the chamber thermocouple for 15-30 seconds.  Once the red display starts to change, the furnace should begin heating when you close the door
  • Occasionally, when the furnace has been idle for several days, the red display is a little slow to respond.  Close the door for 30 seconds, then feel the left, right, top, and bottom walls of the chamber.  They should begin to feel warm to the touch.
  • Check the door interlock.  There is a tab on the lower side of the door, near the hinges.  It should go into a slot on the furnace itself.  Verify that the tab is going in correctly; sometimes the tab will catch and get bent.