Originally Posted by P-J
They both accomplish the same thing. The difference is the second one can be installed in an inexpensive box that is already setup for such a project. Dollars are not thrown away for getting started on an electric brew rig that might evolve and change down the road. Switches are a lot cheaper than contactors and they take up the same room as the switch that would control the contactor in the first place.
My object here is not the "bling" thing but to give brewers options for getting started without throwing tons of cash at it.
This looks great, the PID, SSR, Heat Sink and RTD sensor can be got for about $100. All the switches and plugs would have been needed anyway. Not quite as bad as I was thinking.
Seems as if people are split on using a 25 amp or a 40 amp SSR and Heat sync for a 5500 w element (draw should be 23 amps). I feel like the 25 amp would be fine with the build in factor of safety but feel free to correct me if I'm wrong.
Now that I've got the automation bug I am debating going ahead and setting up a HERMS. I have a 50' 1/2" immersion cooler that I could use as the heat exchanger in the HLT then move to the boil keggle for cooling after the boil is complete. This is the copper I am planning on installing in the HLT for a more permanent solution eventually when I go the counter flow chiller or plate chiller route.
If I were to use a second PID to control the mash temp what is the best way to wire it up (assuming I do need a second PID, SSR, Heat Sink, and RTD)? Does it need to control the pump since the pump will be running continuously throughout the entire mash? Couldn't I just set the HLT at the mash temp (or a few degrees hotter), turn on the pump, then let it run until I am ready to mash out? Would I be able to just monitor the temperature with a PID without controlling the pumps? Sorry for the rapid fire questions, just trying to get some clarification.
I'm also on the fence about the whether or not the RTD should be placed on the output of the HERMS coil or the output of the MLT? Most of the information that I've found seems to favor on the output of the HERMS coil but I noticed on Kai's setup that it is on the output of the MLT. He states that when it was on the outlet of the HERMS the temperature always matched what the HLT was at, which makes sense with a big heat exchanger. I could see advantages to both ways. Maybe some trial and error is called for.
I found quite a bit of good information in this
thread regarding PID controls in a HERMS set up.
I am assuming that it would be bad for the copper to touch the electric element so I would need to build something for it to sit on the lip of the keggle and hold the bottom above the element.
Anything that I am overlooking?