Category: Low Pressure

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How many hot water cylinder types is there?

Have you ever wondered about how many types of hot water cylinders there actually is?

We have complied a list of hot water cylinders for you, showing application, benefit and disadvantages helping you make an educated decision before purchasing your next hot water cylinder.

First of all we need to separate the PRESSURE TYPES from the MATERIAL TYPES. In New Zealand one can purchase almost any material type at three different pressures.

Most common pressure types available in New Zealand (Domestic Applications) 

    • Low Pressure, open vented systems where the pressure is provided by a cold water storage tank, open vent or rely on a pressure-reducing valve to reduce the pressure below mains pressure supply.
      Typical Pressure: 30 – 75 KPA, typically 3 – 7.5 metrets Head
    • Medium Pressure, open vented systems where the pressure is provided by a cold water storage tank, open vent or rely on a pressure-reducing valve to reduce the pressure below mains pressure supply.
      Typical Pressure: 75 – 120 KPA typically 7.5 – 12 meters Head
  • Mains Pressure, with a working pressure equal to incoming supply. Pressure can be limited to any requirement but using the appropriate valve work.
    Typical Pressure: Ranging from 120 – 1400 KPA (Domestic Supply is typically 350 – 750 KPA depending on requirement)

Mains pressure water heaters are the predominant type of new installation in Australia and New Zealand.

COMPARISON TABLE OF HOT WATER STORAGE TYPES AT DIFFERING PRESSURES. 

hot_water_cylinders_types

The following hot water cylinder material types are available in New Zealand

   CYLINDER MATERIAL PRESSURE ADVANTAGES DISADVANTAGES
Enamel Lined Low Pressure
Mains Pressure		 – Supply of mains pressure
– Low cost supply Installation
– Very common in NZ		 Requires sacrificial anode
8 – 20 year life expectancy
Copper Low Pressure
Medium Pressure		 – 15 – 40 year life expectancy
– Large Storage at low cost
– Can be used for high temperature power
sources such as wetbacks and solar.		  

– Not suitable for most  modern tap ware
– Requires sacrificial anode
– Low pressure
Stainless Steel Low Pressure
Mains Pressure		 – 15 – 50 year life expectancy
No sacrificial anode required
– Can be used for high temperature power
sources such as wetbacks and solar.		 – Large storage at high cost
– Higher supply cost
– Come with the longest warranties
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Upgrading your sacrificial anode when replacing a hot water cylinder.

hot_water_cylinder_anodeHow would you like to increase the life span of your current or new hot water cylinder by at least 10 years?

Sounds too good to be true? Every hot water cylinder contains a sacrificial anode which prevents the breaking down of the tank and components. As the name suggests “sacrificial” would mean that at some point it would have to be replaced to maintain this form of protection. In the image to the right you can clearly see the difference within 10 years of operation. Most house holders are not made aware of this fact and unknowingly allow the continuation and breakdown of their relatively young or new hot water cylinder.  By replacing this sacrificial rode you can easily add another 10 years to its operation saving significant cash by preventing the breakdown of metals.

The sacrificial anode (also called an anti-corrosion rod) is typically made of magnesium. It it used to attract corrosive elements so that the tank itself will not corrode as quickly. It can be replaced when it is badly corroded.

But when your hot water cylinder is installed in a tight spot with limited height which is the case in most scenarios, how can you replace this rode (typically over 1 meter length) without actually removing / disconnecting (which would cost you more than its worth) the hot water cylinder to fit it in?

Making it easy to change a cylinder anode when clearance is tight.

When is time to replace your sacrificial anodes you might be faced with several challenges. Either HWC_Anodeyou will have to drain and remove the hot water cylinders or you may have to put a hole through the ceiling above for access. So what is the solution? A flexible Anode! this specialized anode requires less than 250mm clearance and can be installed within 1 hour. So whether you have an existing cylinder or getting a new one, why not ask to be upgraded to one of these allowing you to make the replacement when its due? Saving you cash long term!

Please ask our team about this upgrade which can be purchased for under $200 with a new installation.

You can purchase our flexible sacrificial anode here: Flexible Hot Water Cylinder Anode

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Rheem Alpha low pressure made in 1967

Rheem_AlphaHard to believe but we got called to this 48 year old Rheem Alpha hot water cylinder because a mains pressure upgrade was requested and not because it was leaking!

A typical low pressure installation with a vacuum relief valve and 15mm hot water feed to the house. No Seismic restraint or tray despite there being another property underneath. Safe-trays are a required by law in Australia but not in New Zealand if the property affected is not a separate title. We from Hot Water Cylinder NZ still believe this is good practice, ensuring that if and when a leak occurs the water can be managed and drained preventing damage to your own and others property. We are currently offering a FREE CYLINDER TRAY with every mains pressure upgrade! Call us for more info.