Rheem water heater blinking blue light: 1 blink is normal

Short answer On Rheem, Ruud and Richmond status light models, one blue blink every three seconds is "Normal Operation": the pilot is lit. If the knob is still at PILOT, Rheem's fix is to set it to the temperature you want. See what to check

Status light, gas valve LED or display

1 blink

“Normal Operation”

Owner can check

Printed on 15 model series · 8 documents

Rheem Professional Classic Series Ultra Low NOx Skinny Models, Ruud Professional Achiever Series Ultra Low NOx Skinny Models, Rheem PERFORMANCE Ultra Low NOx High BTU Models with Installed Side Water Connections, Rheem Professional Classic Series Ultra Low NOx High BTU Models with Installed Side Water Connections, Ruud Professional Achiever Series Ultra Low NOx High BTU with Side Connections Models, Rheem Performance Ultra Low NOx Skinny, Rheem Performance Series: Ultra Low NOx, Rheem Professional Classic Series: Heavy Duty Ultra Low NOx, Rheem Professional Classic Plus Series: Heavy Duty Ultra Low NOx, Ruud Professional Achiever Series: Heavy Duty Ultra Low NOx, Richmond Essential Series: Atmospheric, Rheem Performance Plus Series: Atmospheric, Rheem Performance Plus Series: Ultra Low NOx, Rheem Performance Series: High Demand Ultra Low NOx Atmospheric, Rheem Performance Series: Atmospheric · AP23698 p. 24; AP22858 p. 23; AP23699 p. 24; AP19928 Rev 02 p. 24; AP16801-2 (08/14) p. 24; AP17110-1 (01/15) p. 24; AP20849 Rev 02 p. 24; AP23060 Rev 01 p. 24

Legend on the gas control label, as reproduced in the manual; printed in blue, except in AP17110-1 (01/15), which prints no colors.

The lamp blinks 1 time, then pauses. It shows the count only, not the color; the timing on your board may differ.

What it means

One blue blink every three seconds is the code Rheem calls “Normal Operation”. The label legend prints it in blue, and the table under it reads “Normal Operation Temperature knob in pilot position and pilot is lit” (AP23060 Rev 01, p. 24). The label shows it as the “Normal Operation” example next to a “System Problem” example.

Two notes beside the legend tell you how to read the color: “If the Status Light is not blinking blue, relight the pilot.” and “If Status Light blinks red more than one flash every three seconds, see Use & Care Manual.” (AP23060 Rev 01, p. 24). Blinking is also how the lighting label tells you the pilot has caught: you hold the knob in until the STATUS light begins to blink, then check the flame through the sight glass (AP23060 Rev 01, p. 17).

The row describes the knob in the pilot position, and its only fix is to set the knob to the setting you want (AP23060 Rev 01, p. 24).

Check these first

1. If you smell gas, stop and follow the steps at the top of this page.
2. If the knob is still at PILOT, set it to the temperature you want; that is the table’s only step for this row (AP23060 Rev 01, p. 24). The control leaves the factory at its lowest setting, and the recommended starting point is 120°F (49°C) (AP23060 Rev 01, p. 18).
3. Mind the scald risk. Water above 125°F (52°C) can cause severe burns or death from scalding, and households with small children, disabled or elderly persons may need a setting of 120°F or lower (AP23060 Rev 01, p. 18).
4. To check the result, run a hot water faucet and hold a thermometer in the stream. Maximum water temperatures occur just after the burner has shut off (AP23060 Rev 01, p. 4).
5. If the water is still not hot enough, the “Before You Call For Service” chart lists causes an owner can check: water usage may have exceeded the heater’s capacity, so wait for it to recover; the gas control may be set too low; or hot water faucets may be leaking or open, so make sure all of them are closed (AP23060 Rev 01, p. 23).

When to call a licensed technician

• Not for one blue blink by itself. The table gives it only the knob setting (AP23060 Rev 01, p. 24).
• Low gas pressure. The chart’s fix, “Check gas supply pressure and manifold pressure.”, is a gas measurement for a technician (AP23060 Rev 01, p. 23).
• A tripped combustion shutoff system. The chart lists it for not enough hot water and for a pilot that lights while the main burner will not stay lit, with “Contact a qualified service technician.” (AP23060 Rev 01, p. 23).
• Water that is too hot with the knob set correctly. The chart’s other cause is a defective gas control, replaced by a qualified service technician (AP23060 Rev 01, p. 23).

Notes for different models

All eight status light manuals print one blink as normal operation: AP23060 Rev 01, AP16801-2 (08/14), AP17110-1 (01/15), AP23698, AP23699, AP20849 Rev 02 and AP19928 Rev 02 on page 24, and AP22858 on page 23. AP17110-1 (01/15) prints no colors; its notes read “If the Status Light is not blinking, relight the Pilot.” and “If Status Light blinks more than one flash every three seconds, see Installation Instructions.” (AP17110-1, p. 24).

On power vent, powered damper and induced draft models, one flash of the gas valve LED is not normal operation:

Indicator and manuals	One flash	Normal states
Power vent: AP22511 Rev 02, AP23058 Rev 01, AP23057 Rev 01, p. 37	“Low flame signal” (LCD code 12)	Short flash once every four seconds; “heartbeat”
Powered damper: AP15756 (05/10), p. 24	“Control still operating/ Low flame signal”	“Normal Operating Condition/ No Fault Condition”; “Calling For Heat/No Fault Conditions”
Induced draft: AP15696-3 (03/17), p. 28. Also the Ruud manual AP19361 (12/17), p. 32	“Low flame signal (control continues to operate)”	“IDLE (no call for heat, no fault conditions)”; “Call For Heat (no fault conditions)”

For low flame signal, the power vent table’s fixes are raising a low inlet gas supply pressure, raising low supply voltage to the rated voltage, and replacing the pilot assembly (AP22511 Rev 02, p. 37). All three are technician work.

Related Rheem gas tank water heaters codes

• Status light off “Control Off/Pilot Out”
• Status light steady “Pilot recently extinguished and Thermopile is cooling down Temperature knob recently turned to OFF position”
• 2 blinks “Thermopile Voltage Low”

See also

• Water heater size calculator
• 2029 water heater regulations: the DOE standard from May 6, 2029
• Furnace and HVAC tax credits for 2025 and 2026: 25C ended after 2025
• Form 5695 for 2025 and 2026: QMID, lines, carryforward
• Gas water heater pilot won't stay lit: thermocouple, thermopile and the status light
• Home maintenance schedule from the manuals: monthly to yearly
• Winter home maintenance checklist: furnace, boiler, water heater
• Water heater or furnace closet: clearance and air requirements

All Rheem gas tank water heaters codes

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