Ruud 11

What does Ruud 11 mean?

On Ruud RUTGH condensing tankless water heaters, error code 11 indicates the vent pipes on the vent termination may not be connected properly. The controller monitors the venting system, and an improper or loose vent connection at the termination triggers this code so the venting can be corrected before the unit runs.

Symptoms

• 11 shown on the remote control LED display
• Burner does not light or shuts down
• No hot water
• Visibly loose or disconnected vent piping at the terminal

Common causes

• Vent pipes not connected properly at the vent termination
• Loose, separated, or improperly assembled vent joints
• Incorrect vent installation

Diagnostic steps

1. 01

   Note the displayed code

   Record that 11 is shown. This is a venting-connection fault, not a user-serviceable setting.

2. 02

   Visually check the vent termination

   From outside, look at the vent termination for any obviously loose or disconnected pipe, but do not disassemble or alter the venting yourself.

3. 03

   Restart and recheck

   Turn off the faucets, turn the heater off, then turn on a hot water faucet and recheck the display. If needed, unplug for about 30 seconds, plug back in, restart, and recheck.

4. 04

   Contact a dealer or qualified service technician

   The manual's solution for code 11 is to contact a dealer or qualified service technician to inspect and correct the vent connections.

When to call a professional

Code 11 should be handled by a dealer or qualified service technician. Vent connections are safety-critical on a sealed-combustion condensing appliance; an improperly connected vent can leak flue gases and carbon monoxide. The Ruud manual directs vent and safety-device repairs to a qualified service technician and warns against operating the unit if the vent system shows signs of leaking exhaust.