big header tank filling with hot water?

the coil in your hot water cylinder could have split.

bengas
July 2011

exactly what dave said.....

jeff
July 2011

if your hot water is heated by a boiler normally the coil is split inside your cylinder and filling up your cylinder with excess water from the heating system because it has no where to go it travels up that pipe that bends over your tank ,and comes out of there

dave
July 2011