What Does Code 11 Mean on a Tankless Water Heater in Cary?
Rinnai tankless water heater · Cary · October 2026 · Alex · From our service records
What the customer reported
A Cary homeowner called about a tankless water heater showing code 11 on the control module in the garage. He also reported that one of the valves in the master bathroom shower wasn't getting hot water, and that the other side of the home takes a very long time to get hot water.
What we found and did
Alex explained that a code 11 is an ignition issue, and normally it's the flame rods. The tankless wasn't showing the code when he arrived and he couldn't get it to duplicate, so he cleaned the flame rods and gave the homeowner options to swap out the tankless, replace the flame rods, or clean them. In the master bathroom, Alex found the shower valve problem has to be a cartridge issue, but the valve maker is no longer in business, so getting cartridges may be tricky if it's possible at all. The homeowner is deciding between replacing the tankless or just the flame rods, and Alex will call back on Tuesday after looking into the master bathroom fixtures.
