9 Dec 2012: I made the final connections for the plumbing on the external part Saturday Night, and modified them slightly on Sunday Morning. Very Nottingham…. Then the top surface polycarbonate had to be fitted and I got Henry and Joe (visiting for a concert in the Arena, Nottingham) to lift the polycarbonate into place.
I had an email from Stephen F, who has visited my house in the summer. He commented that the flexible pipes have a small internal diameter and could constrict flow, and if there were particles in the circuit, they might cause a clot. I replied with my various reasons for using the flexible pipes.
1. There is some thermal movement in the radiators, so flexible connections remove risk of copper pipes pulling out of joints, and also, with uncertainty about the precise final location of the sunbox on the roof, the flexible joints allow me to make small adjustments.
2. Some constriction of flow is useful to stop the Sunbox 3 pump accidentally pushing liquid through the Sunbox 4 circuit. The pump on the Sunbox 4 will be able to push through the narrow pipes.
3. We have a strainer in the loop next to the GSHP, so any particles get trapped in one location, making it easier for them to be removed at service intervals.
4. Narrow pipes (15mm) allow the warmed liquid to be carried away more quickly instead of sitting in fatter (28mm pipes) losing heat before being delivered to the ground loop.