What do Rinnai tankless error codes mean?

The names below come from Rinnai's diagnostic codes manual. Some codes apply only to certain series, such as the SENSEI line or the older non-SENSEI models, so your controller may not show every one. The manual lists the applicable series in each section.

### Ignition, flame and air

### Overheat and temperature

### Sensors, valves and fans

### Water flow, leaks and drain

### Safety, service and history codes

Fewer than you might hope. Rinnai's manual warns that you must be qualified to service gas systems, and that the electrical, gas and water supply should be turned off before anyone works on the heater. That covers most of the list. But a handful of codes give owners something useful to do.

Read the gas smell rule first. If you smell gas, leave, do not touch a switch, and call from outside. Southwest Gas takes emergency calls at 877-860-6020, and 911 works for any suspected leak.

Then, by code:

• 10, 11 and 12. Check that the gas valve is open, that the propane tank has fuel, and that the vent terminal outside is clear. Turn the heater off and on once. Our pages on each code go into detail.
• 14. Look at the space around the heater for anything stored against it. Then call, since the overheat safety should not trip repeatedly.
• 25. This appears only with a condensate safety switch or an accessory condensate pump. Rinnai's steps are to confirm the pump has power, that the drain line is not clogged or frozen, and that the drain line has an air gap. The pump is an outside accessory, so the pump maker's manual applies to it.
• 79. Rinnai has a technician check the leak detector wiring, the heat exchanger and the internal piping, and look for water pooling in the bottom pan of the cabinet. If you see water leaking from the heater, close the water supply valve to it and call. Water in an electrical appliance is a safety issue.
• SS and LC. These are scale and service reminders, covered on the LC code page.
• FE, 30 and any other flammable vapor code. Leave the space. Rinnai's warning is to stay out of the room until safety personnel have identified the area as safe and the vapors have been eliminated.

Everything else on the list is a sensor, a valve, a fan or the circuit board, and the manual's steps call for a meter, an open cabinet, or replacement parts.

### Which codes let the heater keep running?

Most Rinnai codes stop the burner. Rinnai's manual says the LC codes are the exception: on those units the display alternates between the LC code and the temperature setting, the controller beeps, and hot water keeps coming. The SS service reminder is a time based prompt, so it does not signal a fault. Everything else on the list, from ignition to overheat to the sensors, is the heater stopping itself on purpose.

That makes the resetting question matter. Rinnai's manual gives code 58 as an example of a hard reset, where the power is turned off and back on after the underlying problem is corrected. A code that comes back after a reset is telling you the problem is still there, and repeating the reset only repeats the shutdown.

### How do I see my past codes?

Rinnai's manual describes how to view the last nine codes stored in the controller. Turn the heater off with the On/Off button, then press and hold On/Off for two seconds together with the Up button. The codes flash one after another. Hold the same two buttons to exit, and turn the heater back on. Write the list down before you call. A history of 11, 12, 11 tells a technician something different from a lone 14.

### What is a good habit for the first code?

Write down the code, the date, and what the heater was doing. A code that appeared right after a power blip, a storm, new work near the vent or a long stretch of no use points a technician toward the cause. Photograph the controller if you can. Then reset the heater once, and only once, before deciding whether it needs a visit.

Rinnai's list changes by series, and some models use codes that other models do not. The best source for your heater is the manual for its model, which the rating plate identifies. Other brands use their own numbers. For comparison, Navien's operation manual uses E-prefixed codes such as E003 for ignition failure and E110 for abnormal air pressure. Our pages on Navien error code E003 and Noritz error codes 11, 90 and 99 cover a few of them.

Call when a code returns after one reset, when the heater stays out of service, when you see water inside the cabinet or leaking from it, or for any code that is not one of the owner steps above. HQ Plumbing and Air is licensed and insured, takes emergency calls 24/7, gives free estimates and quotes the price upfront.

Phoenix has hard water, which is behind the scale codes on this list. Our page on how often to descale a tankless water heater in Phoenix gives the schedule, and our page on whether to repair or replace a water heater helps when the heater is old and the codes keep stacking up.

Navien's codes start with E instead, and our list of Navien tankless error codes covers them.