The design of the glycol return trunk lines is flawed. See this post (http://www.homebrewtalk.com/showpost.php?p=5261064&postcount=53) and re-design the return system appropriately. Strike this comment when completed.Design is actually fine. Just be sure that when system is expanded, a LIFO configuration is used to balance pressure.
- Should the bulkhead for the return line be below the reservoir level? This may help keep the return lines full of liquid, ensuring that when the system is modified for multiple tanks that the output of one tank doesn't enter the output of another.
- Worst case scenario, add check valves to each return line before it tees into the main return trunk
- Consider drilling a third hole in the front door of the fridge. Grommet said hole, and pass through both the temperature probe from the FermentPi (for reserve tank temp), as well as 120V power cord for the submersible pump.
- Mount enclosure of FermentPi system to top of the fridge door using 3M adhesive?