Oops. Hot Water Kills Grass.

When I commented on the 11 December 2007 about the solar water heater which The Cottage has I mentioned that the water vented when it got too hot. Subsequently we discovered that the near-boiling water venting onto the roof so forcibly found it's way into places it shouln't have gone. Because it was so hot it also melted the plastic downpipes. They were subsequently replaced by steel ones. This summer the weather has been very hot and the sun fierce and I've been using as much hot water as I possibly can. It doesn't vent now until about 93 deg c which is pretty near boiling point. The problem? It overflows onto the grass: a huge cascade of near-boiling water straigtt onto the grass - presumably because it vents too quickly for the drainage system. It's a good job no-one was underneath at the time.