Rinnai Hot Water Repairs Adelaide: Fault Codes and Honest Fixes

A Rinnai Infinity fails nothing like a storage unit

Continuous flow means no cylinder, no element and no sacrificial anode. Water passes through a copper heat exchanger only while a tap is open. Nothing sits hot for hours corroding a tank, which is why the storage-unit fault list is beside the point here.

• What fails instead is components: the water control valve, the flow sensor, the flame rod, the igniter, the combustion fan and the circuit board.
• Each is replaceable on its own, so a 14 year old Infinity is not automatically finished.
• Scale inside the heat exchanger is the closest thing to a wear-out failure, and it builds with hours of use rather than years on the wall.
• Rinnai also badges storage units, so check what is on your wall before assuming continuous flow.

Rinnai fault codes and what each one is telling you

Read the code off the controller before you phone anyone, because it clears on reset. Code sets vary slightly between Infinity models, but the families below hold across the range.

A code is a symptom, not a diagnosis. Code 11 on a unit that has run faultlessly for 9 years and code 11 on a unit installed last month are 2 different jobs: the first is a component, the second is the gas line, the regulator or the flue position.

The Rinnai complaints that are not faults

A large share of Rinnai callouts find a working unit. Work through this list first, because we would rather you saved the callout.

• Cold water for a few seconds when a second tap opens. That is the cold water sandwich, inherent to continuous flow, and no repair removes it.
• The unit refuses to fire on a trickle. Infinity models need a minimum flow, commonly around 2.5 litres per minute, and a clogged aerator sits under it.
• Lukewarm in the bathroom while the kitchen runs hot. That is the tempering valve, a separate fitting entirely.
• Temperature dropping when 2 showers and the dishwasher run together. A 16 or 20 model is sized for fewer simultaneous outlets than a 26.
• A long wait at a distant tap. That delay is cold water sitting in the pipe run.

Frost, flues and the Adelaide Hills

An Infinity holds water inside its heat exchanger between uses, and that water can freeze. Rinnai builds in frost protection and it is electric: it needs the unit plugged in with the power on. In Stirling, Crafers, Bridgewater, Aldgate and Upper Sturt, where frost is routine several mornings a winter, a unit left unpowered through a cold snap can split a heat exchanger overnight. Never isolate an outdoor Infinity over winter, including on an empty house.

Flueing is the other issue that recurs across Adelaide. These units get squeezed into narrow side passages and tucked under eaves during renovations, and clearances to windows and overhangs are not negotiable. Code 99 on a unit that has always worked and now trips on a still day is usually exhaust recirculating into the air intake.

Repair or replace a Rinnai

The threshold sits a long way out. Because an Infinity is modular, a 15 year old unit with a failed fan motor is worth repairing where a 15 year old storage tank with a rusted cylinder is not. Repair, except in 3 situations.

1. The heat exchanger is scaled beyond cleaning or has split. It is the dearest part and on an older unit it approaches replacement cost.
2. The circuit board has failed on a model out of production and no board is available. Availability ends that, not economics.
3. The unit was undersized for the household from the day it went on. Repairing it buys back a problem you already had.

Other hot water pages

• Heat Pump Hot Water: Heat pump hot water supply, siting and repair across Adelaide. What the running cost really is, where the unit can sensibly go, and when a heat pump is not worth the change.
• Solar Hot Water: Repairs and diagnosis for solar hot water across Adelaide and the Hills: boosters, tempering valves, pumps, controllers, frost protection and evacuated tubes, plus a straight read on when the system is finished.
• Rheem Hot Water Repairs: Repairs to Rheem electric storage, gas storage and continuous flow units across Adelaide, with a straight answer on when the cylinder is beyond saving.
• Dux Hot Water Repairs: Repairs to Dux electric, gas, solar and heat pump hot water units across Adelaide. We read the compliance plate first, because on a Dux it settles the anode, warranty and parts questions at once.
• Bosch Hot Water Repairs: Continuous flow gas repairs by a licensed gas fitter. Ignition faults, flow sensors, blocked inlet filters and hard-water scale on Bosch units across Adelaide.
• Vulcan Hot Water Repairs: Gas storage repairs by a licensed gas fitter. Pilot lights that will not hold, tripped cut-outs, failed gas control valves and anode checks on Vulcan tanks across Adelaide.
• Aquamax Hot Water Repairs: Electric storage diagnosis on Aquamax tanks across Adelaide. Elements, thermostats, cut-outs, relief and tempering valves, plus a straight answer on stainless tanks and anodes.

Questions we get asked