This is an OEM Johnson Controls replacement temperature probe to fit our Controller 11. This is only needed if you have determined your original probe has gone bad (remember, the Controller 11 has a two year warranty).
Testing the Probe
To test your existing probe for proper resistance with a multimeter, you will first need to know how to test for resistance with a simple hand held multimeter (available at any hardware store). Assuming you know how to do this, unplug your Controller II from the wall, and then open the case. Locate where the probe wires are connected to the screw terminals and remove the probe wires with a small screwdriver. Now set your multimeter to the 20k resistance setting on the ohms range, and touch both probe wires with your multimeter. The picture at right shows a multimeter set for 20k resistance with the correct reading for a probe at a temperature of 65-68 degrees F.
The multimeter reading should be as follows:
Temperature at end of probe Multimeter resistance reading (plus or minus 5%)
60 degrees F. 0.96
70 degrees F. 1.00
80 degrees F. 1.04
90 degrees F. 1.09
If you have the probe connected to the multimeter, and you heat the probe, you should see the reading rise confirming proper operation. If you do not get any reading (or a reading of 0.00), or readings are more than 7% off the reading above, replace the probe.