Rinnai INFINITY® N-Series internal and external

Endless hot water, when you need it


Super efficient, super smart

The Rinnai INFINITY N-Series are condensing gas continuous flow water heaters designed for commercial applications and high hot water demand residential installations.

Available as an external unit (N56kWe) or an internal unit (N56kWi).


  • Stainless steel heat exchanger and internal piping
  • Inverted burner, burner cleaning no longer required
  • Inbuilt control panel, parameters easily set
  • Inbuilt temperature sensor
  • Premix burner, no gas pressure setting required
  • Low cost and easy electronic connection
  • Powerful fan allows a lower cost common flue to be installed (available ex-stock)

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Product Details

Suitable for
External commercial and residential applications (N56kWe external model only).

Internal commercial and residential applications (N56kWi internal model only).

Mains and medium pressure systems. Hard or acidic water will need to be treated to use this product.

Condensing technology
Utilises a secondary heat exchanger to drive further thermal efficiency by extracting heat from combusted flue gases, making the N-Series models 97% efficient.

Not suitable
- as spa or swimming pool heater
- for hydronic applications
- for domestic ring main applications1

1 The N-Series internal pump controller is not suitable for domestic ring main applications as it does not allow the system to turn off. This means the ring main continually operates, which can cause high energy use and cost, and can be a noise nuisance, especially at night, when people are sleeping. We do however have a plumbing configuration solution if a domestic ring main is required, click here for more information.

Technical Specifications







Gas type

Available for Natural Gas or LPG, specify at the time of purchase


Gunmetal grey

Factory preset temperature

55 ºC* (can be preset to deliver up to 85 ºC**)

* Models made before May 2020, serial number before 20.05000001 were preset to 75 ºC
** Maximum temp. for circulating systems is 65 ºC

Codes and REU numbers
  • N56kWe external - INFN56N/L, REU-N3237WC-ZK
  • N56kWi internal - INFN56FFN/L, REU-N3237FFC-ZK
Hot water capacity

1.5-37 litres per minute. Nominal water capacity is 32 litres per minute at a 25 ºC rise (1920 L/h)

Exhaust system
  • External unit - forced flue
  • Internal unit - room sealed forced flue
Frost protection

Fitted as standard. Frost protection operates automatically, as long as the appliance is connected to the electrical power supply, by activating when the temperature inside the unit drops below 3.5 °C, and turns off once the temperature inside the unit reaches 7 °C.

Ignition system

Direct electronic ignition

Ingress protection rating


Line pressure (min.)

NG - 1.13kPa, LPG - 2.75 kPa

Line pressure (max.)

3.5 kPa (maximum standing pressure under abnormal intermittent conditions is 5.0 kPa).

In the case of commercial metering, (i.e. 35-37 kPa coming in), there may be a requirement to regulate the incoming pressure down.

Power consumption
  • Normal: 70 W (NG), 85 W (LPG)
  • Standby: 2.4 W
  • Automatic frost protection: 154 W (external), 150 W (internal)
Water supply

Nominal operating pressure: 300-1000 kPa
Minimum operating water flow will depend on setpoint and inlet temp.

Noise level

Internal models 49 dB(A), external model 54 dB(A). Some people are susceptible to low level noise. This needs to be considered if locating an appliance near a bedroom.

Flue combustion analysis

Co/CO2 for nominal conditions:

  • NG maximum load 144 ppm / 9.4%
  • LPG maximum load 95 ppm / 10.1%
Safety devices
  • Flame failure
  • Boil-dry protection
  • Overheat protection
  • Fusible link
  • Pressure relief valve
  • Combustion fan RPM check

29 kg


Energy Safety Supplier Declaration of Compliance: Declaration number - 1911920196

Market release

January 2020


Can an N-Series be used to replace am older unserviceable Rinnai INFINITY in a bank of electronically connected appliances?

Yes, as long as the N-Series is a secondary unit and not the primary. Refer to the N-Series Connection to Older Models document in the Downloads Tab for more information (only accessible to TradeSmart users).

MasterSpec link


CAD/BIM Downloads