In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
closed system layout: do I need a loopback/mix circuit?
installing a Munchkin 50K in a detached garage radiant insulated monoslab. Surfing all over shows SEVERAL different strategies for piping and gadgets. I am pretty handy, I used to sell pipe/valves/fittings in a previous life. I just don't understand the concept of a '"mix'" leg on a closed system. Is it necessary? or just a good idea? or?? please see attached .jpg out of the Munchkin manual. My question is centered around the "'closely spaced tees'" portion of the diagram. I am guessing in theory it is like a car that allows a little exhaust into the intake in order to warm the engine faster (and give the unburned fuel a chance to burn) but... looks to me like the "'path of least resistance'" would be for the heated fluid to run right back to the boiler (especially since the circ pump is pulling on that leg) ?? I am not one of those that has to know every little detail... I can respect that it just needs to happen. But curiosity is killing me :) To add to my confusion, there are diagrams and pictures floating around the web of closed systems that do NOT include this branch of the circuit. Here are the NOTES that accompany the diagram:
1. This drawing is meant to demonstrate system piping concept only. Installer is responsible for all equipment and detailing required by local codes.
2. All closely spaced tees shall be within 4 pipe diameters center to center spacing.
3. A minimum of 6 pipe diameters of straight pipe shall be installed upstream and downstream of all closely spaced tees.
4. The minimum pipe size for connecting an indirect water heater is 1”.
5. The minimum pipe size for connecting the unit is 1.25”.
6. Circulators are shown with isolation flanges. The alternative is standard flanges with full port ball valves. Purge valves can be used with the circulator flanges as an alternative.
7. The anti-scald mixing valve is recommended if the DHW temperature is set above the factory setting of 119oF.
8. Install a minimum of 12 diameters of straight pipe upstream of all circulators.
9. Winterization: When winterizing the unit, put a drain valve on both the supply and return between the union and the shut-off connection.