Stainless Steel Mains Pressure Indoor Cylinders

Endless hot water, when you need it

High quality hot water cylinders

Easy to install, and able to be connected to solar or heat pump installations, they are our premium hot water cylinder

Constructed from high grade duplex stainless steel and packed with features to benefit specifiers, installers and homeowners, making them exceptional value for money.

• Lightweight, stainless steel makes transport and installation a breeze
• Low maintenance, no sacrificial anode to maintain
• Auto-reset thermostat option means these cylinders can be solar or hot water heat pump ready 

The 250 L and 300 L cylinders have the option of a second element making recovery times quicker and making it less likely you'll run out of water.

Install as a low pressure system then connect, without replacing your cylinder, to the luxury of mains pressure when you are ready.

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Product Details

Suitable for 

  • indoor installations only (diam. 550 mm)
  • residential and commercial water heating applications
  • left or right hand plumbing connections
  • connection to open loop solar or hot water heat pump systems

Not suitable as a pool or spa heater. 

Water quality
Rinnai cylinders are manufactured to suit most NZ council water supplies. However some supplies can have a detrimental effect on the cylinder, its operation and life expectancy. Stainless steel cylinders are not suitable for bore or tank water.

Water supplies with a high level of calcium carbonate (hard water) can cause scaling on hot surfaces. We recommend a temperature of no more than 65 °C to minimise scale buildup. Scale reducing or water softening devices should be considered in hard water areas. The unit is not guaranteed against damage due to scaling.


10 Years

IP rating




Cylinder Recovery Times (theorectical)

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

•  135 L = 3 hrs 56 mins (2 kW), 2 hrs 37 mins (3 kW)
•  180 L = 5 hrs 15 mins (2 kW), 3 hrs 30 mins (3 kW)
• 250 L = 7 hrs 17 mins (2 kW), 4 hrs 51 mins (3 kW)
• 250 L = 3 hrs 39 mins (2 x 2 kW), 2 hrs 25 mins (2 x 3 kW)
 •300 L = 8 hrs 45 mins (2 kW), 5 hrs 50 mins (3 kW)
• 300 L = 4 hrs 22 mins (2 x 2 kW), 2 hrs 55 mins (2 x 3 kW)  

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


Not required


Hot and cold water connections ¾ " (20 mm)


Inner cylinder: High grade copper Outer casing


Incoloy 825 alloy sheath element positioned at the bottom of the tank.

Maximum inlet pressure = 120 kPa Maximum working pressure = 120 kPa

Maximum working pressure

850 kPa

Pressure testing

To 15 Bar

Thermal insulation

CFC-free polyurethane foam, compliant with MEPS standard


Robert Shaw 30 A contact thermostat, manually resettable at 85 °C. Thermostat can be upgraded to an auto-reset thermostat for solar and hot water heat pump applications.

TPR valve

Rating of TPR supplied with cylinder— factory set to 850 kPa and 90 °C.


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



Is a safe tray required for a like-for-like HWC replacement?

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

There are so many similar products around, what does Rinnai provide that the others don't?

  • 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.

I'm not really clear on any option and it's all getting a bit too confusing, what should I do?

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.

I’m trying to factor costs and then compare what’s best. I can find out the cost of the different products but what about installation costs?

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 contact a plumber/gas fitter who will be able to explain all the options to you.