Error Code RED 3 FLASHES

Goodman GMEC960803BN Error Code RED 3 FLASHES: Low fire pressure switch stuck open

TL;DR

Low fire pressure switch stuck open

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 RED 3 FLASHES Mean?

Low fire pressure switch stuck open

Common Causes

Cause	Likelihood	DIY?
Faulty pressure switch	Most common	✗ Call a pro →
Pressure switch tubing or wiring/connection issue	Common	✗ Call a pro →
Control board inducer relay failed	Common	✗ Call a pro →
Vent pipe restriction, excessive elbows, or excessive length	Uncommon	✗ Call a pro →

When to Call a Professional

Contact a licensed HVAC technician if:

Basic troubleshooting did not resolve the error
You smell gas at any point during the process
You are not comfortable working around gas lines or electrical components
The unit needs a gas valve, control board, or motor replacement

Sources

Goodman GMEC96 Service Instructions Manual - Two Stage Furnace with Multi-Speed ECM Motor