Rinnai INFINITY® EF24, EF250, EFi250


Condensing continuous flow water heaters, discontinued late 2019, early 2020

Rinnai INFINITY EF condensing continuous flow water heaters capture waste heat from the flue gas through the use of a secondary heat exchanger to help heat the water with less energy.

  • EF24 external superseded by the EF26
  • EF250 external superseded by the N-Series
  • EFi250 internal superseded by the N-Series

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Product Details

Suitable for

  • Commercial and residential applications
  • Mains and medium pressure systems
  • Solar installations as a gas boost

Hard or acidic water will need to be treated in order to use this product.

Not suitable

  • As a spa or swimming pool heater
  • For hydronic applications

Technical Specifications







Preset temp.

55 °C

Gas type

Natural Gas or LPG, gas type specified at the time of purchase

Codes and REU numbers
Model Code NG Code LPG REU number
Hot water capacity
  • EF24, 2.3-30 L/min, nominal water capacity is 24 L/min at a 25 °rise (1440 L/h)
  • EF250/EFi250, 1.5-37 L/min, nominal water capacity is 32 L/min at a 25 °rise (1920 L/h)
Input and output
Model Input Output kW
EF24 162 MJ/h or 45 kW 43 kW
EF250/EFi250 211 MJ/h or 58.6 kW 55.6 kW
Hot water connections
  • Hot water outlet R¾ (20 mm)
  • Cold water inlet R¾ (20 mm)
  • Gas supply R¾ (20 mm) 
  • Condensate R½ (15 mm)
Ignition system

Direct electronic ignition

Exhaust system
  • External unit - forced flue
  • Internal unit - forced flue (balanced flue, room sealed fan assisted), flue diameter; inner Ø80 mm, outer Ø100 mm
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.

Injector sizes
Model NG LPG
EF24 0.90, 1.50 0.75, 1.15
EF250/EFi250 1.15, 1.9, 1.8* 0.75, 1.15, 1.1*

* = only one point

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.

Noise level

50 dB(A). Some people are susceptible to low level noise. This needs to be considered if locating an appliance near a bedroom.

NOx af

less than 60 ppm

Power consumption
  • EF24, normal 50 W, automatic frost protection 118 W
  • EF250, normal 51 W (NG), 62 W (LPG), automatic frost protection 170 W
  • EFi250, normal 72 W (NG), 92 W (LPG), automatic frost protection 218 W

All units have a standby of less than 3 W

Safety devices
  • Flame failure
  • Boil-dry protection
  • Overheat protection
  • Fusible link
  • Pressure relief valve
  • Combustion fan RPM check
Water supply

Nominal operating pressure: 240-1000 kPa
Activation flow rate: 2.4 litres per minute (EF24) and 1.5 litres per minute (EF250/EFi250)

Please note: If the water inlet pressure or flow rate drops below the minimum values stated above, operation of the INFINITY is not guaranteed. The unit requires both minimum flow rate and pressure to operate correctly.


EF24 - 27 kg
EF250/EFi250 - 32 kg


Energy Safety Supplier Declaration of Compliance declaration numbers:

  • EF24 - 1431020135
  • EF250/EFi250 - 1008720096
Market release

EF24 first released in 2008, relaunched 2011
EF250/EFi250 - July 2011

Last sold
  • EF24, Mar 2020, superseded by the EF26
  • EF250, Jan 2020, superseded by the N-Series
  • EFi250, Nov 2019, superseded by the N-Series