Demand Rapid recovery storage system


Smaller commercial rapid recovery storage systems

A complete storage hot water system made up of a Rinnai INFINITY commercial continuous flow gas water heater (external or internal unit), a pump, a thermostat and controller, and a 315 L Demand Duo cylinder.

How it works
The thermostat senses the temperature of the water in the cylinder, and when it drops below the set point, the pump is activated. The flow then starts the Rinnai INFINITY, which returns heated water to the cylinder.

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Product Details

For smaller commercial (small motels), or larger residential where a large quantity of hot water is required quickly, but there is recovery time available before next use. For example filling a machine or filling a spa bath. For commercial applications the water heating system must be sized and installed to written guidelines from Rinnai.

Hard or aggressive water will need to be treated to use this system. If in doubt please test before use.

Not suitable or approved as a pool heater.

There are multiple Demand Rapid systems, too many to list here, than can be made from a combination of the below components. For further details refer to the Demand Rapid flyer within the Downloads tab.

  • INFINITY (boiler) model: HD49, HD56 (external only), N56—available in NG or LPG
  • Mounting: Internal or external
  • Storage cylinder: 315 or 450 L
  • Pump: Single or dual

Technical Specifications





  • Gas - DN20 ¾ " BSP male
  • Cold inlet - DN32 1¼ " BSP female
  • Hot outlet - DN32 1¼ " BSP female
  • Hot water return - DN32 1¼ " BSP female (not used)
  • Condensate - DN15 ½ " (N-Series only)

DN20 ¾ " BSP female
850 kPa, 99 °C, 46 kW


230 V AC GPO


700 kPa (not supplied)


500 kPa (not supplied)

Hot water delivery
  DD1200E315 & DD1200i315 DD1212NE315, DD1212i315 & DD1250E315
Raised 25 °C 1500 L/h 1700 L/h
Raised 35 °C 1250 L/h 1400 L/h
Raised 45 °C 950 L/h 1200 L/h
Raised 50 °C 875 L/h 1100 L/h
Raised 55 °C 800 L/h 1000 L/h
IP rating

IPX4 (cylinder, control box, and Rinnai INFINITY)

System configuration
  • Thermostat pump on 60 °C
  • Thermostat pump off 65 °C
  • INFINITY setting 75 °C
  • Max. outlet water temperature 75 °C
Market release

Top down heating released June 2019 (superseding previous bottom up heating system)