A Complete Guide To Troubleshooting Rinnai Hot Water

 

Rinnai hot water system not working? This hot water brand has built a strong reputation in Australia for reliable, efficient hot water solutions – which is probably why you had one installed! From continuous flow units to storage tanks, solar-boosted systems and advanced heat pump technology, a Rinnai hot water system is designed to deliver years of dependable performance.

But even the best systems can hit a snag, and when they do, knowing the right steps can save you time, stress, and cold showers. If your Rinnai hot water system is on the blink, you’ve found the right place – because our exclusive guide will walk you through:

• The most common Rinnai-specific issues
• What you can check yourself
• And when it’s time to call in a Rinnai hot water expert.

1. Start with the basics

Before diving into detailed Rinnai hot water system troubleshooting, let’s rule out the simple issues:

Power supply:

• For electric or heat pump systems, make sure the circuit breaker hasn’t tripped.
• For gas units with electronic ignition, confirm the unit is plugged in and switched on.

Gas supply:

If you have a gas system, check that the gas isolation valve is open and your gas supply is active.

Water supply:

Ensure the cold water inlet valve is open. If the system has been drained recently (maintenance or repairs), it will need to be refilled before operation.

Controller settings:

For systems with a digital controller, check that:

• It’s powered on
• It’s set to the correct temperature
• It’s showing no error codes.

2. Continuous flow & instant systems

If you have a Rinnai Infinity, B-series, or something similar, the most common faults are related to ignition, flow rate, and temperature sensing. For example, if you’re dealing with a Rinnai B16 no hot water situation, check that:

• The water flow is above the minimum activation rate (usually around 2-3 litres per minute).
• The shower head or tap aerator isn’t blocked, which can reduce flow.
• Gas isolation valves are open and there’s no interruption to supply.
• The hot water controller is on and displaying the set temperature.

Rinnai hot water not working still? If it’s  in a continuous flow unit, an error code on the display can point to the fault.

Common codes cover:

• Ignition failure (code 11)
• Flame loss (code 12)
• Sensor problems (code 34).

3. Storage tank systems

For those traditional gas or electric storage tanks, problems often relate to thermostats, heating elements, or relief valves.

• If you notice lukewarm water, it may be due to a faulty thermostat or a failed heating element.
• On gas storage models, check for a lit pilot flame if your unit uses one, or check ignition status if electronic.
• If your Rinnai gas hot water not working problem includes signs like no pilot flame, repeated flame-outs, or popping/banging noises, it could indicate a gas control fault or sediment build-up inside the tank.

If in doubt, get a licensed plumber out to inspect and rectify.

4. Solar and solar-boosted systems

Rinnai’s solar hot water models pair roof-mounted collectors with a gas or electric booster. Common Rinnai solar hot water problems include:

• Insufficient sunlight combined with a disabled booster – switch the booster on in cloudy weather or high-demand periods.
• Air locks in the solar circuit, which can prevent circulation.
• Pump or controller faults stopping heated water from moving from the collectors to the tank.

Solar systems also need a periodic service to check glycol levels (if applicable), pumps, and temperature sensors. If these aren’t maintained, efficiency and output can drop sharply.

5. Heat pump units

Heat pump water heaters are efficient – but they rely on airflow and ambient temperatures to operate. Blocked air filters, refrigerant leaks, or faulty fans can all result in poor heating performance.

If the unit is running but water stays cold, the refrigerant circuit or compressor may require professional attention.

6. Instant & portable units

A Rinnai instant hot water not working problem can be as simple as low gas cylinder pressure (for portable camping units) or clogged inlet filters.

Always check water and gas supply first, then clean the inlet filter if possible.

7. Hot water controllers

Modern Rinnai systems often use wall-mounted controllers to set water temperatures. Rinnai hot water controller not working?

Check:

• It’s switched on and showing a display.
• The controller cable is plugged in firmly at the unit and controller end.
• There’s no corrosion or water damage at the controller.

If there’s no display, try resetting the system – you’ll be surprised how often that works!

8. Specific Rinnai issues across the range

Some issues are common only across certain Rinnai models. Rinnai Infinity 26 troubleshooting, for example, very often involves:

• Checking water flow rates
• Ensuring sufficient gas pressure
• And clearing blocked inlet filters.

For a Rinnai B26 not working, ignition failures are the most frequent cause – often linked to gas supply issues or a faulty flame sensor.

9. Resetting your unit

In many cases, a simple reset can clear a temporary fault.

• On Rinnai storage models, the Rinnai Hotflo reset button is usually located under the access panel near the thermostat.
• On continuous flow systems, resetting is typically done via the controller – switch off, wait 30 seconds, then restart.

Remember, only reset once, or twice at the max – repeated trips indicate a fault that needs investigation.

10. When to call a professional

While there’s a lot you can check yourself, some problems simply require a licensed plumber or gasfitter.

Call a pro if you notice:

• Persistent error codes that return after a reset.
• Leaks from the unit or pipework.
• Signs of gas leaks (sulphur/rotten egg smell).
• Water temperature fluctuations that don’t match controller settings.
• Unusual noises from pumps, fans, or burners.

Why Fix-It Right for your Rinnai repairs?

Rinnai systems are well known for their superb durability – but when they do develop a fault, they deserve expert attention.

Here at Fix-It Right Plumbing, we work on all types of Rinnai hot water systems – gas, electric, solar, instant, storage, and heat pump. Our fully stocked vans and trained team mean we get to the root cause, not just a quick fix. Whether you need hot water servicing in Melbourne, hot water repairs in Geelong, or hot water system help in Canberra, we fix it right the first time – every time!

Need your Rinnai hot water back fast?

Rinnai hot water system not working? Call the friendly crew at Fix-It Right Plumbing today or book online – and get your hot water steaming hot again.