Rinnai Tankless Water Heater Code 11 Error
What it means
Code 11 is the most common Rinnai tankless error: 'no ignition.' The unit sensed a demand for hot water and tried to fire the burner, but the flame sensor never confirmed a flame. In short, the heater could not light. It almost always points to a gas-delivery problem (supply turned off, low pressure, air in the line) or a dirty/faulty igniter or flame rod — not usually a catastrophic failure. Because it involves gas, treat it carefully: some checks are safe for a homeowner, but anything inside the unit should go to a licensed pro.
The bottom line on the Code 11 error
Code 11 is Rinnai's 'no ignition' lockout, usually caused by a gas-delivery problem — a valve partly closed, air in a freshly serviced line, or an empty propane tank. Because gas is involved, cleaning or replacing the igniter or flame rod means working near the burner and belongs to a qualified Rinnai technician.
Start with the safest step — confirm the gas valve is fully open, then power-cycle the unit; a reset alone will not hold until the cause is fixed. If a tech traces it to the igniter or flame rod, that $150–$400 repair beats replacing a unit under 12 years.
Code 11 snapshot
This is a gas combustion fault — if you ever smell gas, shut off the gas and leave the area, then call your gas utility first; leave the igniter, flame rod, and any internal burner work to a licensed technician.
Our own at-a-glance triage of the Code 11 error, from the verified data on this page. See error-code rankings → · How we score →
Common causes of the Code 11 error
- Gas supply valve to the heater is closed or only partly open
- Low gas pressure, or air trapped in the gas line (common right after gas service or a new tank/install)
- Empty propane tank or a tripped excess-flow valve on an LP unit
- Dirty, corroded, or misaligned igniter or flame-sensing rod
- Blocked or improperly sized intake/exhaust venting starving the burner of combustion air
- Loose or corroded wiring at the igniter, flame rod, or gas valve
Which Rinnai tankless water heaters get the Code 11 error
Code 11 is common across Rinnai's residential tankless lineup — the older R/RL series (RL75i, RL94i) and the current RE, RSC, RU, and V-series (such as the V65iN) — on both natural-gas and propane models, since they all use the same no-ignition flame-sensing logic.
How to fix the Rinnai Tankless Water Heater Code 11 error
- 1Confirm the gas is actually onCheck that the manual gas valve feeding the heater is fully open (handle in line with the pipe), that other gas appliances in the home work, and — for propane — that the LP tank isn't empty and its valve is open. This is the single most common, and safest, fix.
- 2Power-cycle the unit to clear the lockoutTurn the heater off at its switch (or unplug it / flip its breaker) for about 30–60 seconds, then power it back on and call for hot water. Code 11 is a lockout, so a reset is needed after you correct the cause.
- 3Purge air from a newly serviced gas lineIf the code appeared right after gas work, a new install, or a refilled propane tank, there may be air in the line. Cycling the unit a few times often lets it draw gas through, but if you smell gas at any point, stop and call your gas utility or a plumber.
- 4Check the venting for blockagesLook at the outdoor intake and exhaust terminations for nests, snow, leaves, or debris, and make sure nothing is blocking airflow. Inadequate combustion air can stop ignition.
- 5Have a tech clean or inspect the igniter and flame rodIf gas and venting are fine, the igniter or flame-sensing rod is often dirty or failing. Cleaning or replacing these parts means opening the front cover and working near the gas/burner assembly — best left to a qualified Rinnai technician.
🧰 When to call a professional
Call a licensed plumber or Rinnai-authorized technician if Code 11 returns after you've confirmed the gas is on and reset the unit, if you ever smell gas (leave the area and contact your gas utility first), or if the fix requires opening the cabinet to access the igniter, flame rod, gas valve, or wiring. Gas appliances carry gas-leak and carbon-monoxide risks, so internal and combustion repairs should be done by a pro — not as DIY.
Rinnai Code 11 vs Rheem Code 11 vs Noritz Code 11: how they compare
How this code stacks up against related error codes for difficulty, urgency, and cost.
| Rinnai Code 11 | Rheem Code 11 | Noritz Code 11 | |
|---|---|---|---|
| DIY difficulty (1–5) | 5 | 5 | 5 |
| Urgency (1–5) | 4 | 4 | 4 |
| Typical cost | $$ | $$ | $$ |
How much does it cost to fix the Code 11 error?
| DIY fix (open gas valve, reset, purge air) | Free |
| Professional repair (igniter / flame rod + labor) | $150–$400 |
| Replacement (new tankless unit installed) | $1,500–$4,500 |
Repair or replace?
Code 11 is very often a free fix — a gas valve someone left partly closed, air in a newly serviced line, or an empty LP tank — so try those before spending anything. If the igniter or flame rod is the culprit, the parts are inexpensive and the repair is well worth it on a unit under about 12 years old, since tankless heaters commonly last 15–20 years. Only a much older unit already needing other repairs should push you toward replacement under the 50% rule.
Common replacement parts for the Code 11 error
| Flame rod / electrode kit | $23–$75 | OEM Rinnai part; proves the flame | |
| Igniter | $45–$90 | If burner never sparks to light | |
| Plumber / Rinnai tech service call | $100–$250 | Per visit; labor added to parts |
Prices are typical retail ranges and vary by model and supplier — always confirm the exact part number for your appliance before buying. We are not linking parts for this code on purpose: it is a job for a qualified technician, and the right fix here starts with a diagnosis, not a purchase.
Rinnai Code 11 error — FAQ
＋ − What does Code 11 mean on a Rinnai tankless water heater?
Code 11 means 'no ignition' — the unit tried to light the burner but no flame was detected. It's most often caused by a gas-supply issue (valve closed, low pressure, or air in the line) or a dirty/faulty igniter or flame rod.
＋ − How do I clear Rinnai Code 11 myself?
First confirm the gas valve to the heater is fully open and other gas appliances work. Then power-cycle the unit off for 30–60 seconds and back on, and run hot water. If the code keeps returning, the igniter, flame rod, or venting needs a closer look by a technician.
＋ − Why does Rinnai Code 11 keep coming back?
A repeating Code 11 usually means an unresolved gas-delivery problem (low pressure, air in the line, empty LP tank) or a dirty/failing igniter or flame-sensing rod. Once the underlying cause is fixed, the lockout clears after a reset.
Sources & manufacturer references
This guide is independently written and not affiliated with Rinnai. Always unplug appliances before servicing and follow your model's manual. Error codes and steps can vary by model — when in doubt, consult a qualified technician.