Ruud Water Heater Code 11: What It Means and How to Fix It

By Dan Mercer · Published October 5, 2026 · Updated October 6, 2026 · Codes covered: 11 · Sources

Verify in your manual: Ruud's Tankless Water Heater Error Code List names code 11 No Ignition. The owner fix (gas shut-off valve not fully open) comes from the RUTG Use and Care manual linked on Ruud's product page. Code charts differ by series (RUTG, RUTGH, mid-efficiency); check your Use and Care manual.

Code 11 on a Ruud tankless gas water heater is "No Ignition": the heater tried to light the burner and couldn't, so it stopped and left you with cold water. The one fix Ruud's manual gives owners is to make sure the gas shut-off valve on the heater is fully open, then reset the unit. Anything past that (gas pressure, gas piping, the igniter) is a job for a licensed technician.

This 3-minute fix saved 0 homeowners a technician visit this month.

What the 11 code means

Ruud's tankless customer support page links a "Common Error Codes" list. That list names code 11 "No Ignition."

Ruud tankless heaters have no pilot light. When you open a hot tap, the heater sparks to light the burner. If no flame appears, it shuts down and shows 11 on the remote.

The Use and Care manual linked on Ruud's RUTG product page gives owners one cause and one fix for code 11: "The gas shut-off valve is not fully opened." The fix is "Check shut-off valve and open completely."

Look-alike codes that mean something different:

• 12: Ruud's list calls this "Flame Failure." The manual ties it to interrupted gas service, or LP gas running low on propane models.
• 10: "Air Supply or Exhaust Blockage" on Ruud's list.
• 90 or 99: the manual says the air intake or vent exhaust may be blocked. Ruud's list calls 99 "Blocked Flue Fault."

Code charts differ between Ruud's tankless lines (RUTG, RUTGH and older mid-efficiency models). Check the "Service Error Code Chart" in your own Use and Care manual.

Likely causes (most common first)

1. The gas shut-off valve is partly or fully closed. This is the cause Ruud's manual lists, often after other work in the house.
2. No gas getting to the heater. The gas is off at the meter, service was interrupted, or a propane tank is empty. Ruud's list starts with "Ensure you have gas to the appliance."
3. Air in the gas line, common after installation or gas work. Ruud's list says to "Bleed all air from gas lines," an installer's job.
4. Wrong gas pressure, or a gas line, meter or regulator that's too small. Ruud lists both for code 11.
5. Wrong gas type. Ruud's manual warns that a natural gas water heater won't work safely on LP, and vice versa.
6. Poor electrical ground. Ruud's list says to "Ensure appliance is properly grounded."
7. Igniter, igniter wiring, or gas solenoid valve trouble. These are internal parts on Ruud's list that a technician has to check.

How to fix it, step by step

Try a hot tap after each step. If you smell gas at any point, stop and get out.

1. Do the reset from Ruud's manual. Close all hot taps, press POWER ON/OFF to turn the heater off, wait about 5 minutes, turn it back on, and open a hot tap.
2. Fully open the gas shut-off valve. If it was closed, follow the Operating Instructions label on the heater:
   1. Turn off all electric power to the heater.
   2. Turn the gas shut-off valve clockwise to OFF.
   3. Wait 5 minutes to clear out any gas. If you smell gas, stop and follow the gas-leak steps at the top of this page.
   4. Turn the valve counterclockwise to ON.
   5. Turn the power back on.
3. Don't force a stuck valve. If the handle won't turn easily, leave it and call a technician.
4. Confirm you have gas. If no gas appliance works, call your gas utility or propane supplier.
5. Think about anything that just changed. A new install, a meter swap, gas work, or a propane refill all point to air in the line or a valve that wasn't reopened. Call the installer, and don't loosen fittings to bleed the line.
6. Check the power. Direct-vent indoor models use a three-prong cord, which should be plugged into a matching grounded outlet. Make sure the breaker is on.
7. If 11 keeps coming back, call for service. Ruud's manual says to turn off the tap and heater, note the code, and call for service.

Test the part

The parts behind code 11 (igniter, gas solenoid valves, burner) sit inside the cabinet, next to live gas and 120-volt wiring. These aren't homeowner tests. Ruud's manual warns not to attempt repairs on electrical wiring, gas piping, burners, vent connectors or other safety devices. Here's what you can check safely:

1. Unplug the water heater and turn off the gas. Pull the plug (or switch off the breaker on hard-wired outdoor models), then turn the gas shut-off valve clockwise to OFF.
2. Look over the power cord and outlet. Check for cuts, scorch marks or a missing ground pin.
3. Look at the gas line from the outside only. Check for a kinked or crushed line. Don't tighten or loosen anything. If you smell gas, leave and call the gas supplier from outside.
4. Check the vent and air intake outside. Make sure snow, leaves or nests aren't blocking them. Ruud's manual says the air intake needs 12 inches (30 cm) of clearance.
5. Look for signs of water or fire damage. Ruud's manual says to turn off the manual gas shut-off valve if the heater has been through overheating, fire, flood or physical damage. Don't use it again until a qualified technician checks it.

Leave the cover on. Igniter and gas valve checks need live power and gas, so there are no meter readings to give here.

When you're done, follow the Operating Instructions label to turn the gas back on and restore power.

Safety notes

When to call a pro

Call a licensed plumber or gas technician if:

• Code 11 comes back after the reset, with the gas valve fully open and your other gas appliances working.
• The heater is new, was recently converted, or the gas was just worked on. Bleeding air from the line and checking gas type are installer jobs.
• You suspect low gas pressure or undersized gas piping. Checking that needs a gauge and a licensed gas pro.
• The next step would mean removing the front cover, or you see scorching or water damage.
• The heater is under warranty. Have the model number, serial number and installation date ready.

Ruud's manual says to direct questions and repairs to your installer, plumbing contractor or licensed service agent first. For an existing Ruud tankless heater, Ruud's support page lists 1-866-720-2076, 7 a.m. to 7 p.m. Central, 7 days a week.

FAQ

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