Originally Posted by rcm_rx7
Yeah that's true. My reason for wanting it is only to see how close to boil I'm getting, and maybe to monitor temps during cooling and whirlpool. Might now be worth the hassle, and extra hole in the Kettle.
If you are using RTDs, you could put a 3-pole, double throw switch (3PDT) in the box to select one probe or the other. RTDs are more tolerant to long wires and switches/connectors in their path than thermocouples are, so it would probably work.
But, remember.... each temp probe might (probably?) have a static error on it. I've used a couple of different probes and they all had different error values, from 0.5*F to 2.5*F. You can program the PID to account for the error, but if you are switching probes, then they could each have different error values.
But, if the BK probe is just to estimate how close to a boil you are and how close to pitching temps you are, then maybe the error on that probe can jus tbe left as an error and you can tune the PID for the other probe.