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Why Hot Water Cylinder Failures Are Increasing

In an article published on Christchurch City Council, there are rising incidents of hot water cylinder failures. The report says that Christchurch’s water supply has been temporarily chlorinated, which led to the failures.

The Christchurch City Council is looking into this problem and they have determined the reasons for the breakdown of hot water cylinders.

Hot Water Cylinders Failing

Historically, Christchurch has been dealing with issues concerning hot water cylinder failure. Some parts of the city, such as Cashmere, have been affected more than others.

Authorities from the Christchurch City Council are hard at work trying to determine the scale and potential causes for the increase in hot water cylinder failures in the past several months.

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Potential Causes for the Failures

Multiple factors may cause hot water cylinder leaking, which then requires for it to be replaced. These include: the type of cylinder, the age of the cylinder, the chemical composition of the water, whether or not there is debris in the cylinder, and the quality and thickness of the copper used in the hot water cylinder,

The City Council has been working closely with manufacturers. They have now uncovered that majority of the hot water cylinders that are breaking down are those older, low pressure, copper cylinders.

How Water Chlorination Affects Hot Water Cylinders

Some parts of New Zealand that have chlorinated water are not experiencing significant numbers of hot water cylinder failures. The reason for this is the chemical composition of water supplies around the country varies from place to place.

Auckland and Wellington use surface water or water from rivers and streams. This creates a protective film when it comes into contact with copper plumbing. Christchurch uses groundwater from aquifers.

Meanwhile, pitting corrosion that leads to pinhole failure usually happens in some bore water or underground supplies.

Hastings and Napier, for example, have bore water supplies. They have also experienced an increase in hot water cylinder failures following the chlorination of their water networks. In the Napier and Hastings area, the number of failing cylinders has decreased over the year after water chlorination was done.

Here’s What the Christchurch City Council Says

The Christchurch City Council has given this advice to people who needed to repair or replace their hot water cylinder:

“We understand that having to replace your hot water cylinder is a costly exercise and we also acknowledge that there has been an increase of hot water cylinders failing since the introduction of chlorine.

“It’s important to remember there are multiple factors as to why pitting occurs in hot water cylinders. These include: chemical makeup of the water, age of the cylinder, type of cylinder used, debris in the cylinder, and the quality and thickness of copper used. Because of this, the Council is not compensating property owners.

“We are continuing to monitor the situation and work with manufacturers and suppliers to gain further understanding. Work is also progressing on our well head remediation programme to reduce the chlorine levels in our water.”

Do You Need to Replace Your Hot Water Cylinder?

Certain cylinders are sold in areas where pitting corrosion is prevalent. If you need to replace your hot water cylinder, contact Hot Water Cylinders NZ to get the best choices for your area. Options may include stainless steel or enamel-lined steel cylinders.

Does Chlorine Affect Gas Systems or Pipes?

This is one of the more common questions that residents ask. Does the chlorine that is reacting with copper in hot water cylinders also impact gas systems or pipes?

So far, there has been no increased number of failures in copper heat exchangers in copper water pipes, gas continuous flow units, or other fittings.

Conclusion

The Christchurch City Council states, “We agree that the presence of chlorine in the water, along with the other factors, such as temperature, details of installation, and water chemistry, has contributed to the observed pitting corrosion. We similarly agree that pitting corrosion of hot water cylinders is likely to become more frequently observed.  Whether or not this extends to other copper plumbing fittings is yet to be determined.”