What does Goodman code 3 Flash mean?
Goodman furnace code 3 Flash means the pressure switch remained open when it should have closed on the supported control family. Confirm the model number and diagnostic chart inside the furnace door before replacing parts.
What causes Goodman code 3 Flash?
- A blocked intake or exhaust vent
- A restricted condensate drain or pressure hose
- A weak inducer motor or pressure switch
Can I troubleshoot Goodman code 3 Flash?
- With the furnace off, check outdoor intake and exhaust openings for snow, ice, leaves, or nests.
- Replace a visibly dirty air filter, restore power once, and note whether the code returns.
How much does Goodman code 3 Flash cost to fix?
A pressure switch replacement typically costs between $175 and $900 nationally.
When should I call a technician?
Call a technician if the vent is clear and the pressure-switch code returns; combustion-air testing requires instruments.
Symptoms this code causes
Sources and model scope
Fault codes vary by model and control board. Confirm the diagnostic chart inside your furnace panel or the official manual before acting.
Scope used here: DM80HS-style integrated controls using the documented 1–8 flash chart.
- Daikin Comfort Technologies: DM80HS Single-Stage Multi-Speed Gas Furnace — Product Specifications
SS-DM80HS · The 1–8 flash integrated-control family documented for DM80HS-series furnaces; sister-brand models must use the same control chart.
Compiled by Warmlo Editorial · Reviewed August 2026
This is general information, not professional advice. Gas, electrical, and combustion repairs can be dangerous — when in doubt, call a licensed technician.