Low Pressure Copper Indoor Cylinders


Manufactured in NZ since the 1930's

Extensive range of capacities (9-225 L) and sizes means hot water cylinder replacement is easy.

Easy installation as connection to existing plumbing is easy with triple inlets, just choose left, right, or bottom for your cold water inlet.

Undersink range
Perfect if you need a little extra hot water—four sizes available 9-44 L.

Wetback options
Many wood, pellet fires, or burner systems can have a wetback fitted to them. A wetback can work as a valuable supplement to your hot water system.

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Product Details

Suitable for:

  • low pressure indoor residential and commercial water heating applications
  • maximum operating pressures up to 76 kPa
  • left, right, or bottom plumbing connections

Not suitable as a pool or spa heater.

Technical Specifications


5 years

IP rating



Not required


Hot and cold water connections ¾ " (20 mm)


Inner cylinder: High grade copper
Outer casing: Galvanised steel


Incoloy stainless alloy steel

Operating pressures

Maximum inlet pressure = 76 kPa
Maximum working pressure = 76 kPa

Thermal insulation

CFC-free polyurethane foam, compliant with MEPS standard

Thermostat standard

7 " Cotherm probe 20 A over-temperature thermostat, manually resettable at 85 °C

Thermostat wetback

7 " Cotherm probe 20 A (no over temperature)

Model Weight empty Weight full
9 L 7 kg 16 kg
14 L 8 kg 22 kg
22 L 9 kg 31 kg
44 L 11 kg 55 kg
90 L 16 kg 106 kg
135 L 21 kg 156 kg
180 L 26 kg 206 kg
225 L 31 kg 256 kg
Cylinder recovery times (theoretical)

Based on a thermostat temp. setting of 60 °C and an incoming water temp. of 15 °C.

  • 9 L = 37.8 min (1 kW)
  • 14 L = 44.4 mins (1 kW)
  • 22 L = 1 hr 10 mins (1 kW)
  • 44 L = 1 hr 10 mins (2 kW)
  • 90 L = 2 hrs 22 mins (2 kW)
  • 135 L = 3 hrs 32 mins (2 kW)
  • 180 L = 4 hrs 44 mins (2 kW), 3 hrs 9 mins (3 kW)
  • 250 L = 4 hrs 23 mins (3 kW)

No cylinder wrap required. All Rinnai cylinders meet the NZ Minimum Energy Performance Standard (MEPS).


In all Rinnai cylinder instructions, we mandate the use of a drip tray. This is because all cylinders have the potential to leak water and cause extensive damage.

Our instructions state:
The Rinnai warranty does not cover any consequential loss from leaks to the cylinder, so it’s important a suitably drained drip tray/catch pan is fitted as per AS/NZ 3500.4:2015 5.4 and G12/AS1 6.11.3.

Like-for-like replacements are a grey area as most installers will only replace the cylinder to the same configuration as the cylinder that is being replaced. In these instances, Rinnai still maintains that a drip tray should be fitted. This protects the homeowner and the building from any future problems should a leak occur. If a drip tray cannot be fitted, then look at other possible options such as:

• Locating the cylinder outside
• Using a continuous flow gas hot water heater
* As the world’s largest gas appliance manufacturer, Rinnai is widely regarded as the industry leader.
* Rinnai products are known throughout the world for their superior quality, safety, technology and sophisticated control systems, all factories are ISO 9001 and/or ISO 14001 certified.
* We have an established 40 year history in New Zealand.
* Rinnai are happy to advise that we now have an IANZ accredited Test Lab for MEPS testing on Hot Water Cylinders. The lab uses the latest in test equipment and can test all type of Hot Water Cylinders for MEPS heat loss testing.
We realise there's a lot of information out there. Water heating is important and it's better to spend the time up front deciding on what you need and what's important. We have an experienced customer service team that can walk you through the process. For those more complicated projects we also have a free specification service.
Give us a call: 0800 RINNAI ( 0800 746 624 )

Installation costs are difficult to provide as every installation is different. Factors such as the length of pipe required , whether you have accessories fitted, how far away you live and choosing an internal or an external unit all influence the overall cost.

If you’re interested in a Rinnai hot water heating solution, we highly recommend you get an installer to come on site and provide a quote. Call our customer service team (0800 746 624) who can provide options for installers in your area.

Why Rinnai?

Our stylish and efficient heating and cooling solutions are designed to bring you total home comfort.


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