Error Code 5 Blinks
High

Rheem RGRA-07EMAES Error Code 5 Blinks: Twin Fault

TL;DR
Your Rheem RGRA furnace is showing a twinning fault. The twin configuration on the control boards may be set incorrectly. A technician needs to check the twinning setup.
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 5 Blinks Mean?

A 5-blink pattern on the Rheem RGRA-07EMAES's green STATUS LED indicates a twin fault. This code relates to the twinning feature, which allows two furnaces to operate together as a paired system to provide greater heating capacity.

If your furnace is set up as a twinned unit, this fault can occur when the TWIN setting on one or both IFC (Integrated Furnace Control) boards is not properly configured, when the twin wires between the two units' TWIN terminals are not connected, when the transformers of the two units are out of phase (which can also cause the flame LED to appear dim), or when the two IFC boards have different part numbers.

If your furnace is a single (non-twinned) unit, this code typically means the TWIN switch or setting on the control board is accidentally set to the ON position when it should be OFF. A technician needs to verify the twinning configuration matches the actual installation — either properly configuring a twinned setup or ensuring the TWIN setting is off for a single furnace.

Common Causes

Cause Likelihood DIY?
TWIN switch set incorrectly on IFC (ON when should be OFF, or vice versa) Most common ✗ Call a pro →
Twin wires not connected between TWIN terminals on both IFCs Common ✗ Call a pro →
Transformers out of phase in twinned setup Uncommon ✗ Call a pro →
Mismatched IFC part numbers in twinned units Rare ✗ Call a pro →

When to Call a Professional

Contact a licensed HVAC technician if:

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Sources

  1. Rheem RGRA/RGRB/RGTA/RGRS/RGTS/RGRT Installation Instructions

✓ Verified against manufacturer service manual — March 2026