Error Code 1 Blink
High

Ruud UGRA-07EMAES Error Code 1 Blink: Soft Lockout

TL;DR
Your furnace tried to ignite four times and failed, entering a one-hour safety lockout.
Disclaimer
This article is for informational purposes only and does not guarantee the accuracy or completeness of the information provided. Always turn off power and gas supply before attempting any repairs. If you smell gas, leave immediately and call your gas company. Consult a licensed HVAC technician for diagnosis and repair. Any actions taken based on this information are at your own risk.

What Does Code 1 Blink Mean?

A 1-blink code on the Ruud UGRA-07EMAES indicates the furnace attempted ignition four times with the gas valve opening for only 9 seconds during each trial. After all attempts failed to produce a sustained flame, the system entered a one-hour soft lockout. The blower and induced draft blower will run for 180 seconds as part of the shutdown sequence.

The most likely cause is a worn-out or cracked hot surface igniter that can no longer reach the temperature needed to light the gas. Igniters degrade with each heating cycle and typically last 3 to 5 years. A gas valve that fails to open, or opens only partially, can also prevent ignition. If the first ignition trial fails, the installation instructions advise checking for 24VAC across the valve terminals on the IFC to verify the gas valve is being energized.

The furnace will automatically attempt to restart after the lockout period expires. If the lockout recurs, a qualified HVAC technician needs to test the igniter resistance, verify gas valve voltage, and inspect the control board for proper operation.

Common Causes

Cause Likelihood DIY?
Faulty igniter Most common ✗ Call a pro →
Gas valve not opening Common ✗ Call a pro →
Faulty control board (IFC) Uncommon ✗ Call a pro →

When to Call a Professional

Contact a licensed HVAC technician if:

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Sources

  1. Rheem RGRA and RGSA Series Installation Instructions

✓ Verified against manufacturer service manual — March 2026