Heating System Manifold

I am designing a five zone heating system, and bought the parts necessary to hook up all five pumps. Not only was it rather expensive, but assembling that many joints would be time consuming. Instead, I decided to weld up two manifolds (one for supply and one for return). Each manifold is simply a 12" long 1.5" nipple with four 3/4" nipples coming off of it (actually two nipples cut in half as threads are only needed on one end). The fifth connection is provided by a 1.5" to 3/4" adapter screwed onto the end. Together, the two saved me 14 fittings and 24 joints as well as being a fair bit lighter and more compact. To get the nipples attached solidly, I printed out a paper template of the shape they needed to be ground to and taped them on. This made getting a good fit simple and was rather easy to produce, as the 1.9" outside curve of the 1.5" pipe projected onto the 3/4" nipples is just an ellipse.

Getting the welds airtight was a little bit of work, and you can see the pressure testing setup I used. Some old washer hoses were the easiest way to seal the 3/4" nipples, and while they looked comical it worked fine.