Rinnai hot water: what the range actually covers, and what to ask for
Most people arrive at this brand through the word Infinity and assume it means one product. It is a family name inside a range that also includes heat pumps, solar and storage tanks — so picking Rinnai still leaves the real decision unmade.
Rinnai is a manufacturer, not a type of hot water system, and in Australia its residential range spans six distinct families: gas continuous flow, electric continuous flow, electric heat pump, solar, storage tanks and controllers. That matters because saying "we're getting a Rinnai" narrows almost nothing. The decision that changes your daily life — continuous flow or storage, gas or electric or heat pump — is still ahead of you, and it is decided by your house rather than by the badge. This page is an independent guide to how the range is laid out and what to ask; we have no relationship with the manufacturer and sell nothing.
What does Rinnai sell in Australia?
The company is best known here for gas continuous flow, which is where the Infinity name comes from, and it publishes a residential range organised roughly like this:
| Family | What it is | Who it tends to suit |
|---|---|---|
| Gas continuous flow | Wall-mounted unit that heats only while a tap is open. Sold under names including Infinity and Flowmaster. | Houses already on natural gas or LPG with little outdoor space. |
| Electric continuous flow | Same on-demand principle, electric element instead of a burner. | Usually a single outlet or a small dwelling — see the caution below. |
| Electric heat pump | Storage tank with a refrigeration unit that moves heat out of the outdoor air. | Houses with clear airflow, a drain, and somewhere the compressor noise will not sit under a bedroom window. |
| Solar | Roof collectors plus a tank and a backup booster. | Suitable roof orientation and room for a tank. |
| Storage tanks | Conventional stored hot water. | Households that need volume at once more than they need never running out. |
| Controllers | Wall pads that set a delivery temperature rather than mixing at the tap. | An accessory to continuous flow, not a system in itself. |
The practical reading of that table: work out the type first, then see whether this manufacturer makes a good one of that type. Doing it the other way around is how people end up with a continuous flow unit in a house that needed volume, or a heat pump wedged into an alcove with no air. Our comparison of the four system types is the step that belongs before this one.
Is "Infinity" a model or a range?
It is a family name, not a single model, and that is the most common source of confusion at the quote stage. Two quotes can both say "Rinnai Infinity" and be for units with different capacities, different gas types and different controller options. A brand and a family name are not a specification. What identifies the actual unit is the model designation on the data plate — and that is what belongs on your quote, not a family name.
How do I find out which Rinnai I already have?
Every unit carries a data plate: a metal or printed label on the casing, usually on the side or underside of a wall-mounted continuous flow box, and on the outer jacket of a tank. It gives the model designation, the serial number and the gas type the appliance is configured for. Photograph it. That single photo answers most of what a technician would otherwise ask you over the phone, tells you whether the appliance is set up for natural gas or LPG, and lets you check that a replacement quote is comparing like with like.
What does a controller actually change?
On a continuous flow system the controller sets the temperature the unit delivers, so you open the hot tap and get that temperature instead of blending hot and cold yourself. That is genuinely useful, and it has one safety consequence worth understanding: bathroom outlets in Australian homes are required to be limited to a safe delivery temperature, which is normally the job of a tempering valve in the pipework. A controller in the kitchen does not remove that requirement, and a controller that lets a bathroom run hotter than it should is a plumbing question, not a preference. If a quote includes controllers, ask where the tempering valve sits in the design.
A caution specific to electric continuous flow
Heating water on demand with electricity takes a large, sustained electrical draw for as long as the tap is open, because there is no tank storing energy up in advance. That is why electric instantaneous units are normally used at a single outlet — a laundry trough, a remote kitchen sink, a granny flat — rather than as a whole-house system. Repurposing one as a whole-of-house solution can run into the capacity of your supply and switchboard, so treat it as an electrical question to be answered before the plumbing one, and get it confirmed in writing.
What to ask before you accept a quote
- The full model designation, not the family name, and the gas type it is configured for.
- Litres per minute at a realistic winter temperature rise if it is continuous flow — the headline flow rate is quoted at a gentle rise and winter mains water is colder.
- Tank volume and recovery rate if it is storage or a heat pump.
- Siting and clearances in writing: gas units vent combustion products and have minimum distances from windows, doors and vents; heat pumps have minimum airflow clearances and need condensate drainage.
- Tempering valve, relief valve discharge and isolation valve — the three items most often missing from a cheap quote.
- The installer's licence number and the compliance certificate for the work.
The controller is showing a code. What now?
Continuous flow units report faults as a code on the controller rather than by simply stopping. Write the code down before you clear it or cycle the power. It is the single most useful thing you can hand a technician, it often distinguishes a supply problem from an appliance problem, and it is the difference between a diagnostic visit and a guess. Do not look up a code and then act on the gas side of the appliance — read it, record it, and pass it on. If the unit is dead with no code at all, check the obvious supply-side things first: the checks that come before calling anyone covers them in order.
How far can you take this yourself?
All of the above. Photographing the data plate, identifying the family and model, working out which type your house actually needs, checking clearances against the spot you have, and getting the questions above written onto the quote are all yours, and none of them needs a licence.
This far, and no further. Installing, replacing or repairing a hot water system is licensed plumbing work in every Australian state and territory; anything on the gas side of a gas appliance additionally requires gasfitting authorisation, and the electrical connection is licensed electrical work. Do not relight a pilot, open a burner compartment, or open the electrical enclosure on an electric unit. The rules and the compliance paperwork are set by each state and territory, so check the requirements with the plumbing regulator where you live and ask for the licence number before work starts.
Frequently asked questions
What is the difference between Rinnai Infinity and a Rinnai storage tank?
Infinity is a family name within the gas continuous flow range: it heats water only while a tap is open, never runs out, and delivers a capped flow rate in litres per minute. A storage tank holds a set volume of already-hot water, which can run out and then recovers. They are different types of system, not different trim levels, and the choice between them is decided by whether your household needs several outlets at once or a large volume in a short burst.
Does Rinnai make heat pump and solar hot water systems too?
Yes. Alongside gas continuous flow, the Australian residential range includes electric continuous flow, electric heat pump, solar and conventional storage tanks, plus controllers as an accessory. That is why choosing the brand does not settle the decision — you still need to work out which type suits your house first.
How do I find the model number of my Rinnai hot water system?
Look for the data plate on the casing — usually on the side or underside of a wall-mounted continuous flow unit, or on the outer jacket of a tank. It carries the model designation, the serial number and the gas type the appliance is configured for. Photograph it: that one photo answers most of what a technician would otherwise ask, and lets you check a replacement quote is comparing like with like.
My Rinnai controller is showing an error code. What should I do?
Write the code down before you clear it or cycle the power, then pass it to a licensed plumber. The code often separates a supply problem from an appliance fault and saves a diagnostic visit. Do not act on the gas side of the appliance yourself — relighting a pilot, opening the burner compartment or adjusting the gas valve is licensed gasfitting work in every state and territory.
Can an electric continuous flow unit heat a whole house?
Usually not, and it is an electrical question before it is a plumbing one. Heating water on demand electrically needs a large sustained draw for as long as the tap is open, because no tank has stored the energy in advance. These units are normally used at a single outlet — a laundry trough, a remote sink, a granny flat. Using one whole-of-house can run into the capacity of your supply and switchboard, so get that confirmed in writing first.
Sources
What this page explains is based on these official sources. If you check one and it does not match what you read here, send it to us and the article gets corrected.
- Rinnai Australia. Residential hot water range (product families)
- Australian Government, energy.gov.au. Hot water systems — types, installation and energy performance
- NSW Fair Trading. Plumbers, drainers and gasfitters — licensing