Walker your system control panel is nearly identical to mine. One side pwm for kettle the other pid for hlt switches at the bottom. I have not yet installed my pid as I am still batch sparging using my kettle to heat water. I am using a dual pole relay for main power on/off as well.
The HLT actually has no heat source because I batch sparge, too. The BK serves as the HEX for the recirculation part. The HLT only needs to hold hot water for a few minutes while I take my first runnings. I'm going to pump the hot water from the BK to HLT to empty out the bK and then pump runnings to BK, and then pump HLT to MLT for batch sparge.
The plan was to eventually add the electronics to make the HLT have a heat source so that the BK didn't have to serve double duty.
After building the manifold, I walked through a session in my head to go over which valves and switches need to be messed with at various times and I realized that even if the HLT was dedicated and electric, I would never need to run the element in the BK and the HLT at the same time. The only thing I would be gaining by putting an element in the HLT and the electronics into the box would be eliminating one pumping step and mot having to move my coil out of the BK before taking 1st runnings.
So, the future plans now are to move the false bottom from my cooler MLT into the non-electric keggle and make that keggle my MLT. The cooler would then be the HLT that only gets a few minutes of use during a brew.
The other thing this offers me is the option building a RIMs tube if I want at a later time and adding the electronics to the box for that as the second electric heat source.
The system would then be able to do all three:
(1) electric HERMS - as laid out already
(2) electric RIMS - if I want to spend more money and do more work
(3) portable propane and gravity - by moving the false bottom back to the cooler for the MLT and sitting the non-electric keggle on the propane burner for a BK.
That third option is what I would need to do if I decide to take the brewery on the road to a gathering of other GRABASS folks.
Nice Job I know from all your posts I have read that you have been working hard on this.
Thanks. I tried to not talk about it toooooooo much because this thing is not some shiny stainless eye candy. It's purpose is to make beer and not gawk at.