Rinnai INFINITY® HD49 Series internal and external


The Rinnai INFINITY HD49 Series are continuous flow water heaters designed for commercial applications and high hot water demand residential installations.

Available as an external unit (HD49kWe) or an internal unit (HD49kWi).


  • Output of 28 L per minute at a 25 °C rise
  • Maximum outlet temperature of 85 °C
  • Designed for easy maintenance and replacement of key components

Product Details

Suitable for
External commercial and residential applications (HD49kWe external model only).

Internal commercial and residential applications (HD49kWi internal model only).

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

Not suitable
– as a spa or swimming pool heater
– for hydronic applications

Accessory note
There are no sideways or upwards flue diverters for the HD49kWe.

Technical Specifications







Preset temp.

75 °C

Gas type

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



Codes and REU numbers
  • HD49kWe external – INFHD49N/L, REU-VCM2837WC-ZK
  • HD49kWi internal – INFHD49FFN/L, REU-VCM2837FFC-ZK
Hot water capacity

1.4-37 litres per minute

Hot water connections
  • Hot water outlet R¾ (20 mm)
  • Cold water inlet R¾ (20 mm)
  • Gas supply R¾ (20 mm) 
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
  • HD49kWe IPX5
  • HD49kWi IPX2
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
  HD49kWe HD49kWi
Normal 66 W 95 W
Standby 2 W 2 W
Antifrost 104 W 120 W
Water supply

Nominal operating pressure: 220-1000 kPa
Minimum operating water flow: 1.5 litres per minute (depends on setpoint and inlet temp.)

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.

Noise level
  • HD49kWe – 54 dB(A)
  • HD49kWi – 52 dB(A)

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

Safety devices
  • Flame failure
  • Boil-dry protection
  • Overheat protection (OHS)
  • Fusible link
  • Pressure relief valve
  • Combustion fan rpm check

HD49kWe – 20 kg, HD49kWi – 20 kg


Energy Safety Supplier Declaration of Compliance declaration number – DEC-000001841X8M7

Market release

Dec 2021