Manifolds and pipe work
We are still seeing some installation pictures where the details of manifold design are not as good as they could be.
Where the flow is more than 3 l/s per jet, it pays to keep the lengths of the flexible 50mm pipes short. Try to avoid sharp bends in small bore pipe. The elbows in the example above are smaller bore than the valves and hoses, maybe only 40-45mm internal diameter. You can lose up to 0.5 metres of head in a single bend like that, at 5 l/s flow.
If you have a TRG on a 30m head, then the "poor" manifold picture would work fine, as the head loss is a very small percentage. But if you were on a 3m head, you would have a huge power loss. The manifold (top picture) is much improved and actually costs much less to do. Better still for these lower head sites is our PVC manifold option below.
Another point that is often overlooked is that flexible pipes need to be supported with a bracket.
On this job below we noticed that our valves have been removed and that the pipework was not supported.
All the weight of the pipes and water will result in serious jet alignment issues and the turbine will lose efficiency. Shall we say “room for improvement” on this job.
Tip – Make a larger timber base. You then have a rigid surface to support the pipework from.
Note the contrast between these jobs and the recent triple Scottish install and the NZ install that follows. Rigid pipes with large radius, swept bends and all well supported.
