MP indoor SS twin coil for wetback and closed loop solar Ø550mm

Overview

Discontinued

Superseded Jul 2022 by the improved Ø560mm cylinders.

Twin coil systems, save money on power in summer using solar water heating through the standard coil, and in winter heat the water by the wetback fire using the thermosiphon coil.

The thermosiphon coil for wetback has the water circulating through a coil inside the cylinder by a thermosiphon effect, i.e. warmer water rises and cooler water falls, creating a natural flow. This means there's no need for a pump to circulate the water, you can still heat your water even if there's a power cut.

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Product Details

Suitable for:
- indoor installations only
- mains and low pressure systems
- connection to a wetback fire and closed loop* solar system
- residential and light commercial water heating applications

No suitable as a pool or spa heater, or for underfloor heating.

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.

* For closed loop solar systems the heat transfer fluid is circulated through the solar collector on the roof where it is heated by the sun. The heated transfer fluid then passes through the cylinder coil, which acts like a very large element to heat the water.

Twin coil lower element
For new builds and renovations connecting to a wetback fire and a closed loop solar system, where the homeowner will have full electric boost when there is not enough heat from the supplementary heating sources.

Twin coil dual element
For new builds and renovations connecting to a wetback fire and a closed loop solar system, where the homeowner wants faster recovery times, and to reduce the risk of running out of hot water. Cylinder will have higher running costs. 

Twin coil upper element
For new builds and renovations connecting to a wetback fire and closed loop solar system, where the homeowner relies heavily on heat from the supplementary heating sources. Upper element is only used to quickly heat water in the top of the cylinder.

Technical Specifications

Warranty

10 years

IP rating

IPX1

TPR

supplied


Twin coil lower element codes
  • 250 L 2 kW - MS250550CCT20
  • 250 L 3 kW - MS250550CCT30
  • 300 L 2 kW - MS300550CCT20
  • 300 L 3 kW - MS300550CCT30
Twin coil upper element codes
  • 250 L 2 kW - MS250550CCTU20
  • 250 L 3 kW - MS250550CCTU30
  • 300 L 2 kW - MS300550CCTU20
  • 300 L 3 kW - MS300550CCTU30
Twin coil dual element codes
  • 250 L 2 kW - MS250550CCTD20
  • 250 L 3 kW - MS250550CCTD30
  • 300 L 2 kW - MS300550CCTD20
  • 300 L 3 kW - MS300550CCTD30
Construction

Inner, high grade duplex stainless steel
Outer, galvanised steel

Insulation

CFC free polyurethane foam, compliant with NZ MEPS

Connections

Hot and cold connections ¾ " (20 mm)
TPR ¾ " (20 mm)

Coil wetback
  • Wetback thermosiphon coil 1 " 25 mm diameter
  • Length = 10 m (0.785 m2)
  • Maximum kW rating 13.4 kW
Coil solar
  • Solar coil ¾ " 20 mm diameter
  • Length 14 m (1.1 m2)
  • Maximum kW output 21.4 kW
Element

Incoloy 825 alloy sheath element, options; 2 kW, 3 kW, 2 x 2 kW, and 2 x 3 kW

Thermostat

Robert Shaw 30 A contact auto-reset (red dial)

TPR

TPR supplied, 850 kPa, 99 °C, 46 kW

Pressure limiting valve

This cylinder MUST be installed with a 500 kPa or less pressure limiting valve and appropriate cold water expansion valve

Weights
Model Empty Full
250 L 55 kg 305 kg
300 L 62 kg 362 kg
Compliance

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

Market release

September 2017

Superseded

Superseded Jul 2022 by the improved Ø560mm cylinders.

Common spares
  • Thermostat Robert Shaw red dial (ART solar) - 30015
  • Element MP SS 2 kW curved - 30002
  • Element MP SS 3 kW curved - 30004
  • TPR MP 850 kPa HT575 20 mm 99 °C, 46 kW - BE11004781