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PID Thermocouple Issue

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British Steel

Active User
Active Member
May 12, 2011
Hi ddicky the polarity is correct. Already checked that.

Sent from my SM-G955U using Tapatalk
It sounds like the polarity isn't correct, ddicky maybe right... have you tried swapping the wires, never mind the colour code or just gone by wire colours?
If the wires are swapped, you'll have positive feedback instead of negative so it won't stabilise, and the TC input will be getting an inverted voltage, which it may not be expecting nor capable of coping with.

Try reversing the TC wires and repeat your ice-water test?

Dave H. (the other one)


Active Member
Active Member
Aug 3, 2017
No offset.

Yes the substitute TC was wired directly to the PID.

No the humidity is not that high. I've never had a static issue here especially in the summer months.

I'm going to contact the vendor tomorrow and see what they have to say.

Hopefully they will replace the control. I get mine from Amazon for about $20 including the TC. With Prime I never have problems with returns of any kind.

40% or higher Relative Humidity will significantly reduce static charges and the resultant damage to electronics.

Very sorry we have not been able to get your project up and running.


Active User
H-M Supporter-Premium Member
Nov 23, 2013
Can you get a stable reading if you twist the ends of the cable together without the thermocouple in the oven connected?
Dumb question time - you don't have a 2 wire RTD by chance in the oven?


Active User
H-M Supporter-Premium Member
Dec 3, 2013
Thanks everyone for all the suggestions.

I spoke with Aubers tech support this morning and they concur that the controller if faulty and have sent me a return shipping label.

As to the polarity, it is correct. Early on in my troubleshooting I tried reversing the leads. The Kiln TC is easy to confirm the correct polarity with a magnet.

I did the ice water test with a sealed general purpose TC with factory lead. I use these on my smoker controller and I know it is a good TC. The reading dropped from 85 to 21 and then bounced between 25 and 1. This is the TC that I left in the ice water for several hours and as the water warmed up the reading continued slowly drifted low.

Hopefully I will have a replacement in the next week or so.


Active Member
Active Member
Aug 19, 2017
I cut and pasted a GENERAL schematic together to help a DIY'er oven builder get started. There are 1,000 of ways to do it, and 100X more options for parts and choices. Wire sizing, fuses, component ratings etc are not done.

I like the contactor to disconnect power from the Oven as one loads and unloads it. Keeping power on the controller to display the temperature is practical.

There is no LOTO devices in here. To be in compliance , you will need to unplug the oven and attached a certified LOTO device. Procedure for this needs to be in formal LOTO policy documents. I mention this for 2 reasons. -1- You don't ask me why I left it off and -2- you think about LOTO and the need to understand it.

Comments and questions welcome. There should be some Redlines in there.

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