I'm wondering how i can test a thermocouple and a uv flame sensor with a DMM. I've got both on a seed dryer that i'm trying to troubleshoot. I'm meeting the gas man down there tomorrow to look at it together. Any help? Thanks in advance.
[This message has been edited by zero76 (edited 05-09-2005).]
I know nothing about the flame sensor...but, for the TC...
A TC works by generating a small voltage, in proportion to it's temperature. This voltage can only be generated if there is a sharp change from one materiel to another. Over time, this 'seam' degrades. First check the TC fo continuity. If good, than check for a steady voltage between the leads. If the voltage fluctuates, or the meter cannot seem to settle on a value, then the TC is probably bad. Ditto if the read-out on a TC meter bounces all over the place.
I believe it's called Constantin or something like that and a typical furnace thermocouple used to generate 15mv and drop the gas valve coil out around 5mv.This was ten years ago on older furnaces,now LEDs flash a code.The tip should be cleaned of soot with steal wool when testing/suspecting or even seeing one IMHO.
[This message has been edited by frank (edited 05-09-2005).]