Why would water be leaking from the back of a cooper tube that comes out of the top of the water heater. The cooper tube has an open end at the bottom and hot water is coming out of it pretty quickly. I have turned off main supply of water. Can you help please.
The water is most likely coming from the temperature and pressure safety relief valve. If there is something to prevent water leaving the heater while it is heating, the expanding water will force water out the relief valve, instead of hydraulically breaking the tank. Once opened, some dirt can settle in the seat making the leak steady. Flushing the seat by lifting the handle may clear it to be able to stop leaking; if not you might have to replace the valve and add an expansion tank to the tank piping. http://www.nationalboard.com/Classics/classic26.htmlhttp://www.stateind.com/parts/tpvalves.htm
Cheddyman, From wot part of the world do you come from?, What is the brand of HWS?, Is the leak from the back of the pipe or is the leak from the open end? In Australia we have one HWS which is a Coil type HWS, the tank is a low pressure cylinder which has a element, this tank is filled with a combination valve, this valve is also the temperature & pressure releif valve, one entry of the valve feeds the coil. there is a vent in the top of the HWS to allow steam escape and a overflow from the tank from the pressure temp valve. both these overflow points are safety outlets & if blocked are dangerous.