Consider custom,
@legb...
When I designed and built my snowmelt/deicing system for my driveway I needed a manifold and valves that would have full flow with no restrictions, and also had tight sizing requirements. All of the pre-built manifolds (most were SS, made in China) had integrated valves that were not full flow; you can’t have this in a snowmelt system, for in such a radiant heat application, it’s all about the flow.
So I had a set of custom manifolds built; I had to go through a local distributor but the company that built them was called
Alberta Custom Tee. They use a pretty cool machine called a Tee-Puller. The stub off‘s were brazed in place.
http://www.customtee.com/
There are probably a number of firms that can make custom manifolds for you. There are a number of valves you can put on them. You specify all the dimensions including the pipe, the number of take offs, and the spacing; basically everything. You will be able to get
exactly what you want with
no compromise.
The serious old-school commercial plumbers (those who work in copper) will know that there is a portable tool called a T drill, that can do this in the field. But, the custom manifold manufacturers will have this done on a CNC controlled machine similar to what you see in the YouTube video. The brazing is automated as well. Alberta Custom Tee used to have videos on their website of the automated tee pulling machine and brazing, but they seem to be gone.
The valves I chose for my new custom manifolds were made by
Dahl. I was able to choose how they affix to the manifold (I chose threaded) and how the PEX attaches to the other end; I chose compression. However these valves are quite cool: they are modular. There is a valve body, and then on either end you choose the fitting at time of order. In my case I chose a ½" FPT fitting on the input side (to screw into the ½" MPT fittings soldered on the manifold), and then compression fittings for ⅝" PEX. These were very high-quality valves, but they have to be custom ordered through a distributor.
https://www.dahlvalve.com/
At the time I found it all surprisingly easy and more affordable than I thought. Attached here is a photo of the return manifold. Notice the tight spacing; the blue handles indicate return. The PEX attaches to the bottom. Underneath the blue ¼ turn handle is a balancing control. I could not have been more pleased with both the manifold or the valves. All as good as you can get.