What does Rinnai Tankless Water Heater Error Code 11 mean?

An error code 11 often points to a problem with the fuel going into your Rinnai water heater. Gas may not be reaching your unit or pressure may be too low. An issue with your ignitor or flame rod might also be the issue.

There are a few things you can check yourself to see if there’s a simple answer to your lack of hot water. If these options don’t work, it’s time to call a professional Rinnai tankless water heater expert at Full Stack Plumbing.

Contact us today to schedule an appointment with a Triangle plumber in Durham, Raleigh, Cary, Chapel Hill, Carrboro, Pittsboro, and beyond.

What Do I Do if Error Code 11 Shows Up on My Rinnai Water Heater?

An error code showing up on your Rinnai Tankless Water Heater can cut off your hot water in an instant. Besides frustrating everyone in the family, an error warning may be pointing to a serious problem.

When a Rinnai unit flashes an error code 11, it may be indicating one of several types of issues. There’s usually either a problem with the gas supply (propane or natural gas) or with the ignition of that gas.

There are a few things you can check yourself, but you should have some experience in plumbing before taking on more complex problems.

You can poke around and end up voiding the manufacturer warranty on your Rinnai water heater. You could endanger yourself and your family when working around these combustible fuels. Always call a professional plumber when you are unsure of what to do.

Here are some of the most common Rinnai tankless water heater problems that lead to an error code 11:

  • No Gas – You can check your gas valve going into your tankless water heater to make sure it’s turned to allow gas to flow. In a newly installed gas water heater, the lines can also have air in them and they would need to be cleared.
  • Incorrect Gas Pressure – If the gas lines don’t deliver enough pressure, your water heater will warn you with an Error Code 11. Your lines may be obstructed and not be letting enough gas through. A problem could exist in the main line outside your home.
  • Ignitor Issue – It’s important to confirm that the ignitor is providing a spark. Carbon build-up can leave an ignitor unable to ignite the gas that is entering. Your ignitor would need to be cleaned.
  • Flame Rod Issue – The wiring leading to the flame rod could be damaged. Dirt on a flame rod or the gasket would have to be cleaned before the water heater would work properly again.

These and other inspections are usually better left to the professionals. The skilled plumbers at Full Stack Plumbing would also check other potential issues. The ventilation for your Rinnai tankless gas water heater could be blocked and causing the error code. Drainage for the unit’s moisture might also be obstructed.

Our experts like to start with the simplest fixes first We never want to provide you with repairs and part replacements that you really don’t need.

Expert Rinnai Tankless Water Heater Repair at Full Stack Plumbing

Our expert plumbers are happy to come to the rescue when your family is suddenly deprived of hot water.  We can tell you what error code 11 and other error codes mean and get to work finding the exact problem.

We are locally owned, and our staff is fully licensed and certified. Full Stack Plumbing offers affordable prices. We also practice transparent pricing. This means you’ll know what you’re paying for and what services you’ll get for your money.

Contact Full Stack Plumbing for Rinnai Water Heater Repair

If your Rinnai tankless water heater suddenly stops working and flashes an error code, don’t hesitate to call the experts at Full Stack Plumbing.

Our team of licensed, trained, and fully insured Raleigh plumbers handle Rinnai water heater repairs and installations in the triangle area, including Chapel Hill, Carrboro, Pittsboro, Cary, and Durham.

Don’t suffer through any more cold showers! Contact us today to schedule an appointment.

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These are our core values, and this is how we build relationships built on trust. We are not a traditional plumbing company, we are associate owned which means that we will always provide you with exceptional service, innovative practices & fair pricing. As water flows, it can cause systems to break down or backup, that’s why Full Stack Plumbing is always on call for all of your plumbing needs in Pittsboro. Simply stated, Full Stack Plumbing will always keep you in the flow.

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When you reach out to us via phone or online through platforms like Yelp, Facebook, or our website, our friendly customer service team will promptly gather your details and help you book a convenient appointment. Choose from our morning or afternoon service windows, and receive immediate confirmation through text.

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On the day of your service, you’ll get a text with your technician’s name and photo, letting you know they are on their way and will arrive within 30 minutes. Our expert technicians will assess the issue and provide you with transparent estimates for different options (good, better, best) without any obligation. If you decide to proceed, we aim to complete most repairs or installations the same day.

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See What Clients Say About Us

Don’t just take our word for it! Read on to see what our satisfied customers have to say about their experiences with us. From our honest pricing to our exceptional service, discover why residents choose us as their trusted local plumber time and time again.
Charles Cockman
Charles Cockman
20:00 07 Aug 25
From scheduling to installation the service was more than acceptable. However I was NOT informed at time of scheduling that the company had changed to flat pricing instead of hourly. Cost of installing a simple kitchen faucet with no connection changes needed. Time of installation was less than an hour for over 300 dollars. Ridiculous
Gail Vanderheyden
Gail Vanderheyden
14:11 12 May 25
They got the job done, but should know better than to come in and out with wet shoes. Should have done better cleaning up afterwards, for the amount of money it cost..
Ann Drake
Ann Drake
22:43 19 May 26
Jacob did a heroic job! He put in a huge physical effort and tried many ways to make something work. He was here a long time.
Michael Santens
Michael Santens
19:49 19 May 26
JJ helped and made the outdoor water faucet work. Also he did a preliminary survey of the house plumbing and provided a plan. He was able to come early and knocked everything out for the better.
Donna Jarmusz
Donna Jarmusz
17:09 14 May 26
Fern was terrific! He explained everything thoroughly and completed the job efficiently and effectively. Great work!
Frank Passarelli
Frank Passarelli
15:15 14 May 26
I recently had my well pump replaced, but I was left with a mountain of problems afterwards. The mud from the well was never flushed out of the system but was forced into my plumbing which caused a bunch of trouble. All this could have been eliminated by flushing the lines before connecting them to the pressure tank under the house. This mud clogged up toilet fill valves. Faucet aerators tub spout aerators, the grit in the water caused damage to cartridges for the sinks. Shut offs. Stopped up the screen on the Rinanni water heater. Kenneth and his partner did a wonderful job, maintaining neatness and professionalism in my home.Full Stack Plumbing has always had my business!
Matthew Scott Myers
Matthew Scott Myers
20:17 12 May 26
Quick to respond. Took care of the problem no problem. Friendly and courteous. Would reccomend.
David Levitt
David Levitt
20:15 12 May 26
Thank you for the great work and expertise
Eric Dean
Eric Dean
14:52 12 May 26
Called first thing Monday for a clogged kitchen sink I couldn’t resolve myself the day before.Woman on the phone was kind, professional - asked a couple questions, took notes, scheduled the appointment for that same morning and mentioned they would text when on the way.2 hours later received the text. 10 min later they arrived. 2 hours later we were back up and running. Total: 830am called, 12:30pm same day, all done…Two technicians arrived who were both professional, kind, and cautious to leave my house exactly as it was when they arrived. Shoes off outside, area rugs shifted out of the way, diagnosis was clear, estimate transparent, work was completed and then they cleaned all surfaces to ensure things were tidy as they packed up and moved the couple rugs back. Great experience!Thanks Fern!
William Hinton
William Hinton
12:39 12 May 26
The team did their job with no issues so I'm happy.
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