View Full Version : thermocouple well ?

03-25-2005, 06:57 PM
I just got a thermocouple and pid from Snowman (Jacob) and I was wondering if it needs to be in a well or something. I just have a little hole in the back of my furnace for it to stick through. Do you just stick the thermocouple in there and let her rip or does it need to go in something?

03-25-2005, 07:27 PM
There's different types of thermocouples. Is your's ceramic or metal shielded? Probe or bulb?

Neither should be in direct contact with the heat source or the side of the oven. Both should be placed at the level of your metal stock for the most accurate reading.

03-25-2005, 07:34 PM
It looks a lot like the one on the left

It does have a little ceramic disc with 2 holes separating the wires.

Hoffman in Warner Robins Ga

03-25-2005, 07:49 PM

I used a well for a while....not with that thermocouple though.

The well will lengthen the life of the thermocouple. As the kiln is heated, if it is oxidation, it wont hurt the thermocouple. It oxidizes to a maximum. However, if the kiln goes into reduction, this oxidized layer will disappear, the thermocouple will then oxidize again...each time getting thinner. At some point, it will just start giving erratic readings and fail.

It will work as is.........

as far as well's, I just used a well liner, bought from omega. (ceramic tube, one end sealed) dont even know what happened to it, if i knew, i'd send it to ya.


03-25-2005, 08:00 PM
If you can find a piece of ceramic tube that would fill the hole in the oven AND allow the Tc to float from it's back disk, that would be perfect. Otherwise, accomplishing either of the two should work well.

03-25-2005, 08:29 PM
Thanks guys. I hooked it up to a transformer and relay and made it go "thunk" by heating the TC. This is gonna be a neat little rig http://bbs.homeshopmachinist.net//biggrin.gif I need to find a box to put the stuff in...
Gonna have to think about hooking it all up properly. The pid will need to be powered up at the start and the relay will control the element. have to figure out how to wire it to a single 110v plug. Probably need to mount a terminal strip in the box...

Hoffman in Warner Robins Ga

[This message has been edited by hoffman (edited 03-25-2005).]

03-25-2005, 08:57 PM
Terminal Strip Yes, or pull the power for the PID off the relay screw.

You can get an 8x8 enclosure at home depot for about 15 bucks. They are meants as more of a junction box, but should work OK.

Anybody comment...does code require a removable inside sheet like the industrial enclosures have?