Rheem Water Heater Fault Codes

Every documented Rheem tankless and tank water heater error code, what it means, and when it needs a professional.

This page covers Rheem and Ruud tankless gas water heaters — the RTG, RTGH, and Prestige series and similar residential models — and the short alphanumeric fault codes their built-in display or optional wired remote control shows when something needs attention. Most Rheem tankless codes are two characters (a two-digit number like 11, or a digit-and-letter combination like 1L or P1), shown directly on the unit's LED display or the remote panel rather than as a blink count. If your installation doesn't have a display or remote connected, check your model's owner's manual for its LED blink-pattern fallback, since that detail varies by unit.

All Rheem codes

11 — No flame detected at ignition
12 — Flame lost during operation
76 — Remote control communication fault
10 — Air flow / venting fault
1L — Scale build-up warning
P1 — Low water flow
14 — Overheat limiter tripped
61 — Blower motor speed fault
29 — Condensate drain / low heat exchanger temp
65 — Water volume control valve fault

Related symptoms

Not sure which code you're looking at, or the display isn't showing anything useful? Start from what you're actually experiencing:

This site is an independent reference, not a substitute for a licensed plumber or electrician. Pages are written with AI assistance from manufacturer documentation and checked before publishing.