Looking for input on maintaining temp settings in current HERMs system

[rodduley]

A little back ground…about a year ago I decided to take the leap into an electric Herms system. At that time I ran across a High Gravity EBC II controller (for those who don’t know the temperature settings is controlled by plugging into a Ranco or Johnson type controller and for boiling it uses a PWM style dial). I am a little “electrically challenged” and thought this pre-built was the simplest way to go. I also know there can be variances in temperature (a couple of degrees) due to set point tolerances in the Ranco and Johnson controllers so I decided that I would go with a 120v PID controller to drive a separate “small HERMs vessel” with a 1800w immersion heating element to maintain precise control over recirculating mash temperature.
In the meantime I purchased a 50 ft. stainless coil that I hope to eventually use as the heat exchange in the HLT once I upgraded to a complete 240v PID control panel (in the future). This got me to thinking, instead of building a small separate HERMs vessel with PID control could it be possible to install the 50 ft. stainless coil in the HLT and simultaneously use the 5500w element installed in the HLT and the separate 1800w PID controlled immersion heater “dropped in” (think heat stick) for faster heating times. And once desired temperature was reached by both the Ranco/Johnson (EBC II) and the 120v separate PID controller would the 1800w immersion heating element maintain the “precise” temperature in the HLT. Do you think this would work? Should I stick with the original small separate HERMs concept? Any feedback is appreciated.

 

[rodduley]

Thought I might try this again. What I would really like to know is do you think the immersion 1800w PID control heating element will keep the water in the HLT within set temperature once the water is heated using both elements. I know I can't heat the entire HLT with 1800w but will it maintain once up to temps?

Thoughts.....?

 

[alien]

1800W will probably be enough, with suitable insulation, unless your set up is very large.

A smaller HEX will be more responsive and less likely to succumb to temperature layering. The main point of having a coil in the HLT, as I understand it, is that it can also be used as a chiller. I am not completely convinced about the merits of that idea either, but maybe that's just me.

 

[rodduley]

I would plan on running a recirculation pump to thoroughly mix for stratification. I was trying to get a feel from those with more experience that if I heated the water in the HLT with both the 5500w and 1800w obvioulsly it will come up to temp quicker but the potential variable temps from the Ranco/Johnson would not hold precise temps like a PID would. With both elements still running would the 1800w PID controlled immersion heater compensate for the variable of the Ranco/Johnso and keep it in the precise temp of the PID setting?