Indirect installation--tell me what to order!

Reyesuela

I have a good plumber lined up (with lots of recc's in the trade) to take on a rather massive plumbing project, one small part of which is installing an indirect hot water tank to my Burnham boiler. He's done lots of plumbing but hasn't installed an indirect tank before, though he's open to it and all his recommendations (again, other trades) say he can do anything well that he decides to take on, even if it's new to him.



He's doing T&M and is having me order the M that's not in his inventory. :) That's fine with me, but I need to make sure I'm getting all the right parts.



I'm getting the Alliance SL 50 gal tank.



QUESTION 1: I assume I also need the T&P Relief Valve 100XL for Alliance AL27SL thru AL70SL Indirect Water Heaters. Correct? Blowing us up is, in general, bad. :)



QUESTION 2: What is the TPI Immersion Control for Alliance SL Indirect Water Heater? Do I need that AND an aquastat? Or is it an aquastat replacement? In that case, should I get it or a 3rd part aquastat?



I also plan to order the TACO 3/4" Series 5122 Low Lead Mixing Valve.



QUESTION 3: Sound good? Is an outdoor reset worth it?



For zone control, I plan to order the TACO 3/4" Sweat 3-Way Zone Valve for priority zoning for the indirect tank.



QUESTION 4: Is that right? I'm assuming I need three way to either let the water go to the house zones OR to heat the water in the boiler. Am I correct, or should I be doing something else?



I was planning on a getting a Honeywell aquastat. But which one??? I have no idea here, frankly. The water temp coming into the house in probably in the high 50s in the winter, and I want mix the water to 115F, while I will keep the water in the tank above 140F and at the most efficient temp for the time of year.



QUESTION 5: Which aquastat should I buy?