HJ Cooper Stainless Steel Mains Pressure Hot Water Cylinders

Model: MS

HJ Cooper Stainless Steel Mains Pressure Hot Water Cylinders


HJ Cooper by Rinnai stainless steel mains pressure hot water cylinders are constructed from high grade duplex stainless steel and packed with features to benefit specifiers, installers and homeowners, making them exceptional value for money.

Peace of mind
This range of mains pressure electric hot water cylinders comes with a 20 year warranty on the inner cylinder*. You won't find a longer warranty on any other electric hot water cylinder in New Zealand! Whats more, it's backed by Rinnai after sales support.

Energy efficient
• Curved element design ensures 98% of water is heated
• Cold water inlet dip tubes deliver water to the bottom of the tank to avoid mixing of water
• No cylinder wraps required, all HJ Cooper cylinders meet NZ MEPS

MEPS = Minimum Energy Performance Standard
Future proof your home 
Connect to a hot water heat pump or solar system with the extra eco inlet connection**, either now or in the future.

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

• Lightweight, stainless steel makes transport and installation are a breeze
• Low maintenance, no sacrificial anode to maintain
• Future proofed, auto reset thermostat option means these cylinders can be solar andhot water heat pump ready

Innovative design
The 250 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 hot water.

* Please see the Plumbers/Owners Guide for full warranty details
** Excludes 135 L cylinder

Model Diameter (mm) Height (mm)
90 L 488 995
135 L 488 1295
180 L 499 1660
180 L 590 1190
250 L 590 1580
300 L 590 1790


Suitable for:
• Indoor installations
• Mains and low pressure systems
• Domestic 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
HJ Cooper water heaters are manufactured to suit most New Zealand council water supplies. However some water supplies can have a detrimental effect on the water heater, its operation and life expectancy.

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


Models and capacities MS13555020 = 135 L (2 kW)
MS13555030 = 135 L (3 kW)
MS18055020 = 180 L (2 kW)
MS18055030 = 180 L (3 kW)
MS25055020 = 250 L (2 kW)
MS25055030 = 250 L (3 kW)
MS30055020 = 300 L (2 kW)
MS30055030 = 300 L (3 kW)
Within the range there are different element sizes and configurations, and thermostat options, please ask in store for details.
Anode Not required
Connections Hot and cold water connections ¾ " (20 mm)
Construction • Inner cylinder: High grade duplex stainless steel
• Outer casing: Galvanised steel
Element Incoloy 825 alloy sheath element positioned at the bottom of the tank.
• 135 L: 2 or 3 kW
• 180 L: 2 or 3 kW
• 250 L: 2 or 3 kW*
• 300 L: 2 or 3 kW*
* Twin element options available
Pressure Testing To 15 bar
Thermal Insulation CFC-free polyurethane foam, compliant with MEPS standard
Thermostat 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.
Weight Empty (approx.) 135 L = 29 kg
180 L = 35 kg
250 L = 45 kg
300 L = 53 kg


Installation Instructions
Supplier Declaration

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