After 12 years continuous operation, what does a Powerspout PLT runner look like.

 1. On the side where sunlight reaches it, despite the force of the water jetting around, there is considerable growth of algae and moss which is not present on the inner side.

Inside face:

Outside face:

2. The amount of wear on those places where the jets hit hardest is negligible. The splitter ridges of the pelton cups are as sharp as in a new runner. In my installation, the water is free of silt and free of lime and that is why the runner maintains such good condition.

Old runner:

New runner:

3. From the way the heads of the stainless steel retaining screws have been polished by water as it emerges from each pelton cup, it is evident that some of the water is directed up toward the shaft. This is important, - because it is this water which can enter alongside the shaft and reach the ‘wet side’ bearing. The V-lip seal on the shaft is placed there to prevent such water tracking along the shaft, and the twin lip seal at the inner end of the ‘Top hat’ assembly is the final barrier stopping water reaching the bearing. Both seals need to be kept in good condition.

4. My conclusion: I was pleasantly surprised by how little wear there was after 12 years of operating 365 days per year. I only replaced the runner so I could thoroughly inspect it, and having seen it's in such good condition, I will put it back for at least a further decade of use.