Rheem RGPH-07EAMGR Error Code Flame LED Slow Blink: Marginal Flame Sense Current

What Does Code Flame LED Slow Blink Mean?

The amber flame-sense LED on the UTEC 1012-925 IFC reports how strong the flame current is. Steady means good current; a slow flash means the current is marginal — the board still sees a flame, but the signal is weak enough that it may drop out and shut the furnace down mid-cycle.

On this single-stage RGPH furnace the flame sensor is a metal rod that must conduct a tiny current through the flame to ground. The most common reason the signal weakens is oxide or carbon buildup coating the rod, which insulates it. Less often the flame itself is weak from low gas pressure, a poor ground connection reduces the signal, or excessive heat at the igniter base (above about 1000°F / 538°C) causes a short to ground.

A marginal signal is an early warning that often precedes a full ignition lockout: if the current keeps dropping, the board can fail to prove flame and enter the 1-hour lockout shown by a single status-LED blink. It is also distinct from a rapidly blinking amber LED, which means flame is detected when none should be present — a safety issue rather than a cleaning job.

What You'll Notice

• The amber flame-sense LED flashes slowly instead of glowing steady during a heat cycle.
• The furnace sometimes shuts off partway through a cycle and then relights.
• Heat is intermittent — warm air comes and goes rather than running a full, steady cycle.
• Over time the furnace may progress to a no-heat lockout if the signal keeps weakening.

Common Causes

How This Is Diagnosed

The cause is isolated cheapest-first. The flame sensor rod is cleaned, since buildup is by far the most common reason for a weak signal. If cleaning does not restore a steady amber LED, a technician checks the ground connection continuity, verifies gas pressure for a strong flame, and looks for excessive heat at the igniter base that can short the signal to ground.

How to Fix It: Clean the Flame Sensor

What You'll Need

• Scotch-Brite pad
• 1/4-inch nut driver or screwdriver
• Flashlight

Steps

1. Shut off power and gas before you start Turn off the furnace power switch or breaker and shut off the gas supply before opening the burner compartment. If you smell gas, leave immediately and call your gas company from outside. Let the furnace cool before you begin.
2. Locate and remove the flame sensor Open the burner compartment and find the flame sensor — a single metal rod at the end of the burners with one wire. Remove its retaining screw and gently withdraw the sensor, noting its orientation.
3. Clean the sensor rod Gently clean the flame sensor rod with a Scotch-Brite pad until the metal is dull-bright. Rheem's guide lists fine steel wool as the cleaning material, but many HVAC technicians prefer a Scotch-Brite pad because it leaves no abrasive residue on the rod. Do not clean or scratch the white porcelain base, and take care not to bend the rod.
4. Reinstall and restore power and gas Reseat the sensor and its screw, reconnect the wire, close the panel, reopen the gas supply, and restore power.

When to Call a Professional

Contact a licensed HVAC technician if:

• The amber LED keeps flashing after the flame sensor has been cleaned
• The flame looks weak or yellow, or the burners seem starved for gas
• The furnace has also started entering the single-blink 1-hour lockout
• The sensor rod is cracked, or its white porcelain base is chipped or burned

✓ Verified against manufacturer service manual — March 2026