When you say isolated, do you mean disconnected? I think this will always lead to the orAL error. To test if the thermocouple is bad, you can just short the thermocouple terminals (4&5) on the PID with a piece of regular wire. This should make the PID think that it's reading close to room temperature. Make sure you have the Sn value set to 0 for a K-type couple. Actually, check that first. If it was set to 20 or higher, it would explain the error code. If it was set to zero and you are using a K-type thermocouple, then the thermocouple is bad if shorting the terminals clears the error.Hubert- this morning I went out and isolated my thermocouple from the PID to see if that may be the culprit; unfortunately it wasn't even after turning it off/on the PV still read 2393F. I did notice that when I turned the power on (each time) I'd get a quick flash of code, then the PV value would read 32F and the SV read o, then there was a slight pause and I could hear a click almost as if a relay was engaging and the PID read the 2393/orAL. I did cut my teeth in BEE (Basic Electricity/Electronics- Analog & vacuum tubes in the military) and know enough to be a serious threat. Hopefully I get lucky real soon- thnx for the intel!!!