Rinnai INFINITY® HD56kWe external

Commercial water heating at its best


Heavy duty on demand for demanding jobs

The Rinnai INFINITY HD56 is an external gas continuous flow water heater designed for commercial applications, and high hot water demand residential applications.


  • Hot water capacity 1.5-37 litres per minute
  • Maximum outlet temperature of 85 °C
  • Status monitor

Read More

Product Details

Suitable for
External commercial and residential applications.

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

N.B: Due to the increased depth and flue outlet position there is no recess box currently available for this unit.

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

Which model does this replace?
Rinnai INFINITY HD250 external

Technical Specifications





Thermal eff.


Preset temp.

55 °C

* Input of LPG model is 20.1-245 MJ/h
Gas type

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



REU number





Hot water capacity 1.5-37 l/min
Nominal water capacity 32 l/min at a 25° rise (1920 l/h)


• Hot water outlet R¾ (20 mm)
• Cold water inlet R¾ (20 mm)
• Gas supply R¾ (20 mm)

Exhaust system

Forced flue

Ignition system

Direct electronic ignition

Line pressures

NG 1.13-3.0 kPa
LPG 2.75-3.0 kPa

Line pressure maximum

3.5 kPa (max. 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 line pressure down.

Ingress protection rating


Power consumption

Normal - 87 W
Standby - 2 W
Frost protection - 88 W

Noise level

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

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.

Safety devices

Flame failure, boil-dry protection, overheat protection (OHS), fusible link, pressure relief valve, and combustion fan rpm check.

Water supply

Nominal operating pressure: 200-1000 kPa
Minimum water flow will depend on setpoint and inlet temp.



23 kg


Energy Safety Supplier Declaration of Compliance declaration number: DEC-000002250L2L2

Market release

January 2023

MasterSpec link

CAD/BIM Downloads