Problem with Thermocouple

I have recently built the po man's electric brew rig and am having problems with my new thermocouple. It is a K type thermocouple that is hooked into a T on the mash tun valve. It is hooked up to an led readout, but i am getting weird readings. When I start up the led it gives me a wrong temperature reading, and then slowly starts to increase. I left it on overnight and came back the next morning only to find it reading 500 degrees! I tried to do some research on the internwebs but couldn't find anything. Any ideas?

You need to provide some details, like type of PID or device reading the thermocouple. Model numbers, etc. Did you set it to read a K type?

Yes, it is a K type

Here is a link to the thermo:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250532311908&ssPageName=STRK:MEWNX:IT

and here is one to the readout:
http://cgi.ebay.com/Digital-DC-Temperature-Meter-K-Type-Thermocouple-F-/250788869820?pt=LH_DefaultDomain_0&hash=item3a642e76bc

These didn't come with any instructions or anything.

In hindsight i should have just bought a PID with a SSR, but oh well.

Doesn't look like you have any calibration or input choices on that thing. I'd say check the probe with a meter but I wouldn't have a clue what it should read as there are many types of K thermoprobes.

It might be a case of you get what you paid for. Maybe someone will have an answer.

Did you get your polarity correct on the thermocouple?

Sent from my DROIDX using Home Brew Talk

yeah, i tried both ways, which both give different but the wrong temperatures

Did you ever get this working? I'm interested in making a cheap digital thermometer with this, but not if it is worthless junk. They don't give much info in the listing.

Is it possible there is a way to calibrate it?

Nope, unfortunately I never did. I cant remember if there is a way to calibrate. I don't think so.