HERMS build - Dual Thermocouple question

1000ml · 09-22-2009, 09:06 PM

I couldn't find anyone doing this so wanted to put it out to the board.

Working on building out a HERMS, borrowing liberally from The Pol and jcdillin.

Basically I want to have 2 thermocouples, one in the HLT for bringing mash/sparge water up to temp and one in the hx return during recirculation. Has anyone put a switch between the 2 thermocouples into a PID?

The PID will always be controlling the temperature in the HLT but have the ability to switch between the 2 temp readings.

Thanks in advance!

Sean

Sawdustguy · 09-23-2009, 09:52 AM

I don't see why it wouldn't work. You will need a switch specifically for your type of thermocouple. A regular switch will not work. Adding another type of metal to the thermocouples will cause inaccuracies.

**Ohio-Ed** · 09-23-2009, 12:02 PM

RTD sensors are more accurate and don't need special wire. They are a bit more expensive though.

**rcrabb22** · 09-23-2009, 03:54 PM

I was planning the same temperature measuring and control for my HERMS system and was going to move my temperature probe from the thermowell in my HLT to the thermowell in my MLT after dough in. My thermowells are open end SS tubes installed in the lids just like Pol's HLT setup (from Brewershardware.com) so the probe should be able to be moved easily.

Orangevango · 09-23-2009, 07:30 PM

the best solution I found was an outlet that you could put into the front of your control panel that connected to the PID. It came with an end to attach to your thermocouple, you buy two of them and attach the ends to two thermocouples so you can plug whichever one you need in at any given time.

freddyb · 09-24-2009, 03:12 PM

I use the panel-mount thermocouple female connector from McMaster on my control box. Part number 3869K48. Seem like it would be easy enough to unplug one and plug another one in. But if you want to put it on a switch, that's cool too.

http://www.mcmaster.com/#3869k48/=3rrwrh