Arising from this topic over in electrics, can anyone tell me the purpose of this setup?
![](//img185.imageshack.us/img185/5490/dsc00128uj8.th.jpg)
When the red knob is twisted, mains pressure cold water goes through the trap. Is this purely a device for unblocking? Seems a good idea if a little odd - certainly never seen it before?
![](http://img185.imageshack.us/img185/5490/dsc00128uj8.th.jpg)
When the red knob is twisted, mains pressure cold water goes through the trap. Is this purely a device for unblocking? Seems a good idea if a little odd - certainly never seen it before?