Cylinders

Q: Can I fix my leaking cylinder?

A: Leaks in a hot water cylinder are usually caused by corrosion or from the action of hot water and pressure. If your cylinder is leaking this is usually a sign that the tank is wearing out and should be replaced. It doesn't make financial sense to repair a tank if it's reached the end of its life, which is generally 20-40 years for electric low-pressure tanks and five to 20 years for mains pressure steel tanks. (For the latter, the valve train may need upgrading to meet modern codes and installation instructions.)
 
Turn off the tap in the piping that leads to the cylinder or the tap that controls the water to the header tank in the ceiling. If you have a mains pressure gas-heated hot water system, cutting off the mains supply will do the trick.

You will have to wait until the water system empties before the flow at the leak slows down. A small leak in a pipe can be temporarily fixed with a rubber patch and metal clamp or sleeve. This should be followed by a permanent repair as soon as possible.

Q: How do I make my electric storage hot water cylinder more efficient?

A: If you put a wrap around it, you will reduce heat loss, which wastes valuable energy. Wraps are available from your local hardware store.

To increase efficiency, the pipes leading from your storage water heater should be lagged for the first 2 m of horizontal piping using pre-formed closed cell foam pipe insulation of 12 mm nominal thickness. This insulation material is available from hardware stores.

If the pipes run upwards first, then horizontally, the lagging will still need to extend to the first 2 m of horizontal piping, as well as the vertical section of pipe.

If the pipes run downwards before you get to the 2 m horizontal length, the downward pipe acts as a heat trap. You do not need to insulate beyond the first 150 mm of the downward pipe. 

If in doubt, ask your Master Plumber to do the job for you.

Q: I've heard it's a good idea to secure my hot water cylinder in case of an earthquake, but how do I go about it?

A: An excellent, practical article on hot water cylinder restraints featured in the June/July 2011 edition of BRANZ Build magazine. Have a read HERE (PDF, 991kb)