Newps wrote:

: No, that's the reading I get. 80 degrees F up to about 250F. And it
: constantly jumps around between those numbers. Every once in a while
: I'll get a normal reading of between 1250-1450F.


This could also be caused by a short in the thermocouple wire at any point,
because the two dissimilar metals in contact are the actual thermocouple
junctions. If the thermocouple insulation is broken allowing the two wires
to short out, you've got an extra thermocouple junction in the loop, and
that could cause readings like you've seen. The short could also be inside
the plastic connector plugs!

You could check this by unplugging the problem thermocouples. You should get
the smallest possible temperature reading in this configuration, no matter
what. If the reading is still jumping around, the problem would have to be
in the wiring from the analyzer to the plug.

Also, on the Omega thermocouples I've worked with, those plugs are two piece
riveted together, so perhaps you could remove the rivets. Otherwise I'd try
carefully squeezing the female plug with pliers to make the female quick-
disconnect a little tighter. This would help bite through any oxide
or dirt.

Good Luck.
--
Aaron Coolidge (N9376J)