What does Daikin code 4 Flash mean?
Daikin furnace code 4 Flash means the high-limit switch opened on the supported control family. Confirm the model number and diagnostic chart inside the furnace door before replacing parts.
What causes Daikin code 4 Flash?
- A dirty or overly restrictive air filter
- Closed or blocked supply and return vents
- A blower, limit switch, or airflow problem
Can I troubleshoot Daikin code 4 Flash?
- Turn the furnace off and replace a dirty filter with the size and type specified for the system.
- Open all supply registers and make sure return grilles are not blocked before trying one reset.
How much does Daikin code 4 Flash cost to fix?
A limit switch replacement typically costs between $150 and $750 nationally.
When should I call a technician?
Call a technician if the limit code returns; repeated overheating can damage the furnace.
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.