Rinnai water heater error codes

Most Rinnai codes are a safety shutdown: the unit found a condition it does not like, turned off the gas and is telling you which system was involved. The number points you to the right area to check. It does not always name the failed part.

A handful of codes are common and have simple causes a homeowner can check. The rest point to sensors, wiring or the control board and need a technician.

How to reset a Rinnai error code

1. Turn off all hot water taps.
2. Press the ON/OFF button on the temperature controller to turn the unit off, then press it again to turn it back on.
3. Open a hot water tap to see whether the unit fires normally.

If the code comes back, the cause is still there. Repeatedly resetting a unit with a combustion or overheating code is not a fix, and it can hide a problem that gets worse.

The codes homeowners see most

Gas and ignition: 11 and 12

Code 11 means the burner did not light, and code 12 means it lit and then lost the flame. Both usually start with the gas supply: a closed valve, an empty propane tank, air in a new gas line or a gas line too small for the heater.

Air and venting: 10

Code 10 points to the air supply or exhaust. Check the vent terminal outside for snow, ice, leaves or nests. On condensing SENSEI models it can also mean the condensate drain is blocked or frozen.

Overheating: 14, 16, 54, 57 and 58

These codes mean part of the unit got too hot. Scale inside the heat exchanger and venting problems are the usual causes. They should be taken seriously and looked at by a technician.

Maintenance: LC and SS

LC means scale is building up in the heat exchanger and the unit needs to be flushed. SS is a service reminder set by the installer. Neither means the heater has failed, but LC in particular should not be ignored.

What you can safely check yourself

• That the gas valve to the heater is open and other gas appliances work.
• The propane tank level, if you use propane.
• The outside vent terminal, for blockages.
• The condensate drain line on condensing models, for kinks, clogs or ice.
• The inlet water filter, which can clog and reduce flow.
• When the unit was last descaled.

When to call a technician

Rinnai's troubleshooting procedures for most codes involve gas pressure testing, measuring sensor resistance and opening the sealed combustion area. Rinnai limits those steps to trained professionals, and doing them yourself can affect the warranty. If a code returns after a reset and the simple checks above do not explain it, call a Rinnai-trained installer.