Is Your Hot Water Cylinder Leaking? Here are 7 Possible Causes

Leaks are never planned and when they happen, the timing is always bad!

This guide will help you identify where the leak may be coming from and what could have caused your hot water cylinder leak.

Whether you use Hot Water Cylinders NZ to do the repair or not, by asking the right questions and/or providing the right information, you will save hundreds if not thousands in repairs or replacement depending on system type and size.

Cause #1: Damage Caused by External Forces

External damage may cause a leak within the hot water system. If your hot water cylinder is relatively new (7 years or less) then the probability of a leak resulting from wear and tear is low.

Some questions you may want to ask yourself are:

  • Have any works taken place on my property? This includes any renovation works etc.
  • Have I repaired or replaced a plumbing fixture? This includes minor upgrades such as replacing a tap to larger upgrades such as replacing a shower. Often such upgrades can result in leaks to your hot water system. Our specialists will quickly be able to investigate through a process of elimination to determine the cause.
  • Has local Council done any upgrades? Watercare can often upgrade public watermains introducing more pressure onto a private property. This added pressure may spring a leak within the hot water system.
  • Is your hot water cupboard often used for storage or drying laundry? It may well be that pipework has been knocked resulting in a loose connection. If this is the case, please don’t attempt to repair this yourself. You may risk the pressure blowing the fitting off which will become very difficult to isolate and will cause flooding.

The good news is that most hot water cylinder leaks can be repaired, keeping your cost low. Time is often of the essence.  If you quickly identify or suspect one of the above external forces to be the likely cause, please let us know at time of booking.

Cause #2: Recent Electrical Repairs or Element Replacement

When the immersion element is damaged due to age, electrical failure or otherwise, an electrician or Limited Electrical License holder such as a plumber will need to replace the element and/or the thermostat.

When this occurs you need to be aware of several things:

  1. Your tank has been under pressure for a long time. This pressure has been consistent but when the element is replaced the tank will “decompress” which results in the movement of all components internally, including the welded seem. Often, cylinders that have had no issues prior to this decompression will start to leak once the cylinder undergoes repressurisation. This expansion and contraction is more than enough to crack a welded seam under certain circumstances.

    We always advise consumers to think carefully about an investment that could require a full replacement a few months later. Often it’s better to make this investment into a new hot water cylinder system than into a repair that represents a third of the total cost. View our “*Is Your Hot Water Cylinder Leaking?” section for more info.

  2. Once the element is replaced, if you find a leak in the vicinity of the element, then the element seals have not been installed properly or could be faulty. This information comes in handy if you recently had your element replaced and have spotted a leak.

  3. Always make sure that your contactor replaces the element with an equal wattage e.g 2kW should be replaced with 2kW and not the more common 3 kW. 3kW elements are cheaper to purchase and corners could be cut which may end up costing you more.  A higher kW rating means more load on your existing wiring and HWC which again due to age may fail.

Cause #3: Safety Valves May Be Operating

We have some great information about cold water expansion valves. Here are a couple of resources:

Cause #4: Vacuum Relief Valves or Open Vents may be Overflowing

If you possess a Low Pressure Hot Water Cylinder then your installation will either include a vacuum relief valve or an open vent.

Cause #5: Age of Your Hot Water Cylinder

If your hot water cylinder is ageing and has sprung a leak, our recommendation is that you save any money you intended to spend on an investigation or repair. Having completed over 5,000 installations to date, our records show that 2 out of 10 repaired hot water cylinders end up being replaced within 3 months of the repair. This of course will depend on the fault, cylinder & environment, but in most cases a plumbing company will charge a fee to investigate and/or attempt a repair if you’re agreeable. It’s best to make sure that you will not be charged before they despatch a technician.  

TAKE NOTE: To attempt to repair a cylinder of this age including replacement of the element may result in unintended additional damage. Element threads are often seized and too much force will crack the internal tank. Low pressure hot water cylinders are often made of copper which is a relatively soft material. It will not take much force to cause a leak.

Cause #6: Watercare & Council Watermain Upgrades

If road works are visible from your home, then there is a high chance your home is affected. Particularly if you notice a leak during or after these works are complete and you didn’t have the necessary protection in place such as a pressure reducing or limiting valve which regulates your incoming pressure.

An increase of pressure may result in:

  • Safety valves suddenly discharging water
  • Open vents overflowing
  • Burst hot water cylinders

To add to the strain, often debris will find its way into households causing other issues such as hot water fluctuation or blockages on valves such as toilet inlet vales and hot water system valves.  If you intend to install a pressure reducing valve, it is highly recommended you also install a strainer which will isolate any unintended debris from entering your home.

 

If you would like more information about Watercare compensation for watermain leaks and processes, please visit the following article: Watermain Leaking? Here is What You Can Do.

Cause #7: Dissimilar Metals & A Failed Sacrificial Anode

Every steel hot water cylinder contains a specialised Hot Water Cylinder Sacrificial Anode. Over time they break down so your hot water cylinder doesn’t. But what happens when are fully broken down? What will protect your hot water cylinder?

Whilst this is one of the causes a cylinder may leak, you may ask your, “well isn’t it a bit late once my cylinder is leaking?” You are absolutely right! This information won’t help if your cylinder is leaking but it will provide you with some knowledge around why it may be and what you can do to prevent it from happening again.

For other faults such as electrical faults or no hot water at all, please visit the following resources:

The above is a short list of causes that apply more than others. We also come across dozens of isolated causes which we have not included due to their rarity.

If you are unsure what may have caused a fault on your hot water cylinder, why not give us a quick call and speak to our highly qualified hot water cylinder specialists?

In many cases we can identify the fault over the phone at no cost to you. Alternatively, in 80% of all cases, we are able to identify the fault over the phone and immediately advise of repair and/or replacement costs. Hot Water Cylinders are New Zealand’s #1 hot water specialists and are ready to assist 24/7.