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How to Identify Hot Water Faults

Hot water is an essential part of our daily routine, and we often take it for granted until something goes wrong. If you’re experiencing issues with your hot water cylinder, don’t worry; there are usually straightforward solutions to fix the problem. In this article, we’ll explore some common hot water faults and how to identify them.

Instant Hot Water Heaters

Instant hot water heaters are a popular choice for many households as they provide hot water on demand. However, they can also experience faults that can disrupt your hot water supply. Here are some common issues to check for:

  • No power to the unit: If your instant hot water heater has no power, it won’t be able to produce hot water. Check that the unit is plugged in and that there is the power to the socket.
  • Reduced water flows: If you’re experiencing reduced water flow, this could be due to blockages in the diffusers or in-line strainers. Clean these out to improve water flow.
  • Run out of gas: If you’re using LPG gas, check if you’ve run out. If so, replace the cylinder to restore your hot water supply.

Gas Cylinders

Gas cylinders are another popular option for heating hot water. However, there are some common faults that you should check for:

  • Pilot flame is blown out: If the pilot flame has blown out, relight it according to the manufacturer’s instructions.
  • Water leaking onto the burner or pilot flame: If water is leaking onto the burner or pilot flame, this can cause it to go out. Check for any leaks and repair them if necessary.
  • Gas meter shut off: If the gas meter has been shut off, your hot water cylinder won’t be able to produce hot water. Check that the meter is on and functioning correctly.

Electric Hot Water Cylinders

Electric hot water cylinders are a reliable option for heating water, but they can also experience faults. Here’s what to check for:

  • Element: If the element has failed, the hot water cylinder won’t be able to heat the water. Check for any signs of damage or wear and replace them if necessary.
  • Thermostat: If the thermostat isn’t working correctly, it can cause the hot water cylinder to overheat or not heat the water at all. Check the temperature settings and replace the thermostat if necessary.
  • Fuse: If the fuse has blown, the hot water cylinder won’t be able to function correctly. Replace the fuse with a new one.
  • Strainers: Check the strainers for any blockages, as this can affect the flow of hot water.

Renovation Work

If you’ve recently had any renovation work done in your home, this could cause your hot water faults. Check that all pipes and connections are secure and that no damage has been done to the hot water cylinder during the renovation work.


In conclusion, identifying hot water faults can be simple if you know what to look for. By checking these common issues, you can often diagnose and fix the problem without the need for a professional. However, if you’re unsure or unable to fix the fault, it’s always best to seek advice from qualified professionals such as Hot Water Cylinders NZ.