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These can be divided into two main categories: Low and High Pressure systems. For gas hot water cylinders please see our Gas section.

Low Pressure

This type of system is typically less than 120kPa. This is very low, in fact most of New Zealand low pressure operates at less than 75kPa.

These tanks are predominantly made of copper and, if they are New Zealand made, are of excellent quality lasting at least 25 years

When doing work on these systems, Your Local Plumber always recommend replacing both valves simultaneously – the pressure reducing/feed/Ajax valve and the pressure relief valve. Replacing these valves is very sensitive and can be dangerous. We cannot state clearly enough that you really need to know what you are doing.

The drawbacks of a low pressure system is the requirement for special tapware in order to have an effective shower, and the inevitable poor pressure on most other taps.

To your advantage is lower power and water bills, saving you money in the long run. There is also the future requirement (2020) to have a water rated system in order to reduce national water usage.

Mains Pressure

Mains pressure is generally rated from 350-500kPa. Naturally the benefits are great showers with good pressure in the kitchen, although this can result in higher water consumption and therefore power bills. Unlike low pressures systems, there is a comprehensive range of tapware available for these.

Cylinders are made from steel and generally last 20 – 25 years. Your Local Plumber’s think the Rheem brand is fantastic. We’ve had a few issues with Coopers over the years, especially with warranties and back-up from the company so we prefer not to use them for your sake.

Would we at Your Local Plumber install a hot water system? Yes. Another 10/10 suggestion.

Hot Water Cylinder Valves

This has become more complex over the years Your Local Plumber has been in business and, by law, this needs to be done a qualified and registered tradesman – after all you don’t really want to blow your house up.

Tempering Valves

This is a great safety measure, especially if you have young children or are slightly older yourself. It’s where a valve is installed on the outlet pipe of your hot water cylinder which is used to directly mix the hot water with cold to ensure the feed to your hot tap is a maximum of 55° Celsius.

Your Local Plumber believes this temperature is great for the shower, but not really effective enough for washing dishes or clothes. In order to enable you to use 60-65° Celsius, we prefer to run a separate pipe from the hot water cylinder to the kitchen and laundry to ensure the water is piping hot.

Does this comply with health and safety standards? Yes, the 55°C rule only applies to personal hygiene activities. Your Local Plumber would also never do anything that would not comply with these standards or the law.

At Your Local Plumber we would rate them 7/10.

How can I tell if I have a high or low pressure hot water system?

Turn your hot and cold taps on full at the same time. If the water flow is the same, you probably have mains hot water. If the hot water is less than the cold, you have a low pressure hot water system.

Learn more on hot water cylinders.


Learn more on replacing hot water systems.