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Gas Water Cylinders and Saftey

dux_hot_water_cylinderThis 1996 Dux Hardie (a james Hardie product) Vitreous Enamel gas hot water cylinder has had several repairs done over the years. Whether it was a failed gas thermocouple, replacing of a down-draft diverter or Piezo ignition device, we always pride ourselves in the ability of troubleshooting by following a simple process of elimination, identifying and fixing gas water heaters.

After a “smell of gas” was noticed, Hot Water Cylinders NZ were called to the scene to investigate and hopefully fix yet another possible fault. After only a few minutes onsite, our installers identified that an overheating issue had caused a “split in the seams” resulting in a drip onto the flame which evaporated, mimicking the smell of gas. This Natural Gas hot water cylinder was naturally redundant!

After a life span of 20 years the owners agreed it was time for a new and more efficient solution.

The first thing I noticed with these image was the quality and safety awareness of the installation itself. Unlike many older gas jobs we come across, no short cuts were taken and no safety measures were avoided which contributed to long life span and safe operation of this appliance on a property that has been purchased and sold over 8 times in the last 20 years.


A quick look on the labels and manual show how important it is for the gas fitter to read and apply manufacturers instructions, these include:

  • For safe operation this water heater must be fitted with…1) Thermostatnatural_gas_cylinder
    2) Over-temperature control
    3) Combination pressure and temperature relief valve

Additional important points include how important it is to get your hot water cylinder serviced, ensuring valves are operating safely giving your hot water cylinder the best chance to provide you with hot water for many years to come.  Relief valves should be checked for adequate performance or replaced at intervals not exceeding 5 years or less in areas where local regulations apply.

With an appliance that includes an open flame (pilot light), safety must be recognized and followed to prevent harm to person and property. For instance, a gas hot water cylinder must be installed on a fire-proof base. The appliance should not be enclosed unless otherwise recommended by the manufacturer and sufficient ventilation has been provided. Operation should never take place with panels or covers removed and anything flammable should not be stored (prevented) in the vicinity of the appliance. It almost sounds like so much can go wrong, which could be true unless the installation company has enough experience to apply a “prevention” mentality which would eliminate all risks by simply following a code of standard.


In this instance the owner of the property decided to switch to a tankless hot water solution. This meant reclaiming of their garage space and all the benefits that come with tankless water heating.

Being able to reuse the existing gas pipe meant savings on the installation. the only thing left was to remove the gas flue and repair the hole left in the roof. After 6 years of history with this appliance, it think deserves a special spot on our blog!