If you smell gas near the heater, stop reading and act: leave the house, do not touch light switches, call 911 from outside, then call your gas utility. Otherwise, a code 11 on a tankless water heater in Sapulpa, OK generally means the burner did not light or did not prove it lit. The two brands whose documents I checked, Rinnai and Noritz, both describe it that way. Other brands may use 11 differently.
First, which brand is on your wall
An error code is a manufacturer's shorthand, so the same number can mean different things on different labels. I read published code documents from two makers and report only what they say. For any other brand, or for your specific model, the manual is the authority.
| Brand | What the documents I read say code 11 is | Where the maker points you |
|---|---|---|
| Rinnai | Listed as "No Ignition" in two Rinnai error-code documents, one for condensing models | Gas on at the heater and meter, gas type and pressure, igniter, venting airflow, scale on the heat exchanger |
| Noritz | Described as an ignition failure: no ignition, or ignition without flame detection | Sight glass, ignition and flame rods, then gas supply, which Noritz says belongs to a professional |
| Any other brand | Not checked | Your model's installation or troubleshooting manual |
Rinnai's lists differ by product line, so match the document to your model number on the data plate. Noritz also publishes a separate article for its Pro Series, with the same basic meaning.
What the unit is trying to do
When you open a hot tap, a flow sensor tells the heater to start. A fan pulls in air, a spark or hot surface lights the gas, and a flame sensor confirms the flame within a few seconds. If lighting or proof fails, the control board shuts the gas and shows an ignition code. That is a safety lockout, doing its job.
So the code does not tell you which part is bad. The cause could be no gas, a dirty rod, a weak spark, restricted air, or a flame sensor that cannot see the flame. The checks below go from simplest to most involved.
Stuck on code 11?
A dispatcher is on the line 24/7. Nobody here will pressure you into a repair, and the price is agreed before work starts.
Safe checks you can do
These need no tools and do not open the gas system.
- 1Look at the display and write down the codeNote whether it clears and returns, and whether it appears on every draw or only some.
- 2Check the gas shutoff on the unitThe valve handle should sit in line with the pipe. Rinnai's document lists gas turned on at the heater, meter or cylinder as a first check. If it was closed, do not hunt for leaks yourself. Open it only if you know it was closed by mistake and smell nothing.
- 3Look at the vent termination outsideRinnai lists restrictions at the vent terminal and around the unit. Clear leaves, a bird nest, snow or stored items from around the outside vent without touching the vent pipe joints.
- 4Reset powerTurn the unit off at its power button or unplug it for a short time, then restore power. The documents I read did not list this under code 11, so treat it as a harmless first try, not a fix from the maker.
- 5Run another hot tapOpen a faucet fully. Weak flow can keep the unit from starting properly, and a clogged fixture screen is easy to rule in or out.
What counts as a stop sign
Some findings end the homeowner part of the job. Stop and call if any of these show up.
- You smell gas or hear a hiss near the heater or its pipe.
- You see soot, scorch marks, a melted vent or water around the burner area.
- The code returns after a power reset and the unit still will not light.
- The flame you see through the sight glass flickers yellow or lifts off the burner.
- Anything beyond the outside of the unit would need to come apart.
Noritz states plainly that troubleshooting gas issues should be left to a professional. That fits with every other gas appliance: adjusting a regulator or testing manifold pressure is not owner work.
What a plumber looks at on the visit
A plumber working on a tankless unit goes through the same chain the makers describe, but with meters and the right tools. On a typical call, expect some of these.
Gas supply and pressure
A manometer reads the pressure at the unit while it fires. A low reading can mean an undersized line, a partly closed valve or a regulator problem.
Ignition parts
The ignition rod is cleaned or replaced. Noritz notes that corrosion or pitting on the rod calls for replacement, and the high-voltage wire and igniter come next.
Flame detection
The flame rod and its wire are inspected. Noritz mentions checking the blue flame rod wire and the green ground wires.
Venting and air
Intake and exhaust runs are checked for blockage and loose joints, which Rinnai lists among its remedies.
Scale on the heat exchanger
Rinnai's document mentions hot spots from scale buildup. A descale flush is a common service item on tankless units.
Mistakes that make it worse
Most bad outcomes start with a helpful guess. Reaching into the burner area with a wire brush can damage the flame sensor. Bridging a safety switch to get hot water is dangerous. Replacing parts at random is slow and can bury the real problem. Changing dip switches without the manual can leave the unit set for the wrong gas type or the wrong model.
Another common mistake is to keep resetting the unit again and again. Repeated failed ignition attempts leave unburned gas in the combustion chamber, so after two or three tries it is smarter to stop.
What the City of Sapulpa and the gas utility say
Oklahoma Natural Gas publishes this advice for a suspected leak: get everyone out of the area right away, do not operate electrical equipment such as light switches, and once you are safely away, call 911 and then the utility at 800-458-4251. If your gas comes from a different company, use that company's emergency number, and keep it on the fridge next to the heater's model number.
The City of Sapulpa's Building Inspections page says plumbing permits are separate from building permits and are requested by contractors licensed by the state and registered with the city, with minor repairs and adjustments the main exception. An ignition repair may count as minor, but replacing the unit or changing gas piping is not, so ask Building Inspections at 918-248-5910 before assuming. Verify any plumber's license with the Oklahoma Construction Industries Board at oklahoma.gov/cib.
Nearby towns and the same code
The same advice applies outside city limits. In Mounds, about 10 miles south-southeast of Sapulpa, a plumber starts with which gas supplier serves the house, since the emergency number differs. In Glenpool, where the city requires contractor registration, ask that city's permit office if the repair becomes a replacement.
When to call, and what to tell the dispatcher
If the quick checks do not clear the code, have the brand, model, the code, and what you already tried ready. Mention any odors or noise. Our tankless water heater page covers installs, flushes and repairs, and the water heater repair page explains how a diagnostic visit usually goes. The 24/7 line at (855) 575-2890 is open when the hot water quits at night too.
Sources and standards
Error code meanings come from the maker's own documents, including Rinnai and Noritz materials that list code 11 as an ignition problem, and gas work follows NFPA 54 and the unit's installation manual. For which code edition the city enforces, the building inspections office is the source, and the state board is the source for licenses.
Code 11 questions
No. Rinnai and Noritz both describe it as an ignition problem in the documents I read, but other makers assign their own meanings. Check your model's manual for the code list.
Turning the unit off and on is a common first try and is low risk if you smell no gas. If the code comes back right away, stop and call. Repeated retries do not fix a gas, rod or vent problem.
Rinnai lists scale-related hot spots on the heat exchanger among its remedies for its code. Whether scale is your cause takes a plumber's inspection, and your local water supplier can tell you about its water quality report.
Noritz describes cleaning it with a rough sponge, but that means opening the cabinet. Many owners leave it to a plumber, and if the unit is under warranty, check the manual first.
Call the 24/7 line at (855) 575-2890. A dispatcher will take the details and arrange a licensed plumber. Meanwhile, keep the unit off if it keeps failing to light.