The Rinnai INFINITY A-Series and EF-Series are continuous flow hot water systems for residential applications. These water heaters produce endless hot water, and unlike electric cylinders, are energy efficient as they are only on when you need hot water.
There are five models to choose from in the A-Series depending on your hot water needs. Model numbers represent hot water capacity, for example the A24 produces 24 litres of hot water per minute at a 25 ° Celsius rise.

The INFINITY A28i is for indoor installation only and can be hidden in a cupboard, or up in the attic. Installing your Rinnai Infinity A28i gas hot water unit inside provides proximity to outlets (taps) and gets your hot water to you faster.
Appliance output of 28 L per minute (at a 25°C rise)
Ability to reduce input to 26 L/min and 199 MJ/h when closer flue clearances are required
Suitable to use as a solar boost for solar thermal installations.
Maximum outlet temperature of 85°C
Adjustable wall brackets to allow easy alignment of existing water, gas and flue connections
Simplified commission of internal appliances. Switch flue length settings without switch gas pressure setting
Inbuilt controller for operating parameters and service & fault diagnostics

There is one option in the EF-Series which is an external gas condensing continuous flow hot water heater making this more efficient as it uses waste heat from combustion to pre-heat the cold water coming in. 
All Infinities come with inbuilt frost protection and electronic ignition (electrical supply required).

Options available are Compact Controller, Bathroom Deluxe Controller and Kitchen Deluxe Controller.

Infinity A28i (and other Infinities) specs at a glance

Warranty

Installation Guide

Operations Guide