Hi there
I hope this bit of information helps you.
The “noise” the water heater is making when water is being drawn off is a rumbling and banging noise – kinda like someone banging a bit of steel with a hammer?? If this is the case then your cylinder is full of lime or calcium chunks that are banging about in the tank. There is no real effective way to clean this out of a gas cylinder and the net result is a new cylinder when you can stand the noise no more. Over time the heater will become less efficient as it fills more and more with the hard calcium that attaches itself to the lining of the tank.
When you get round to replacing the tank I would recommend you ask your Plumber to fit a water softener to prevent a reocurrance of this problem.
Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians