Daikin Air Conditioner Error Code H3

The H3 code indicates a high pressure switch system abnormality, specifically that the high pressure switch in the outdoor unit is showing no continuity while the compressor is stopped. This is a safety-related fault that prevents the system from operating. It typically points to a wiring, connector, or switch component issue rather than an actual refrigerant overpressure event.

No, you should not continue operating the unit while the H3 code is active. The high pressure switch is a critical safety component designed to protect the compressor and refrigerant circuit from dangerous overpressure conditions. Running the system with this fault present bypasses that protection and could result in compressor or system damage.

A power reset may temporarily clear the H3 code, but the fault will return if the underlying problem has not been corrected. The control board detects the open circuit in the high pressure switch circuit at startup, so if the switch, wiring, or connector is still faulty, the error will reappear quickly. A reset is only a useful step after the root cause has been identified and repaired.

Some causes of H3 can be addressed without special tools, such as reseating the high pressure switch connector at X32A on the outdoor unit PCB. However, testing the switch for continuity and inspecting the wiring harness requires a basic understanding of electrical diagnostics and a multimeter. Any work involving refrigerant or PCB replacement should be handled by a licensed HVAC technician.

Repair costs vary depending on the root cause. If the fix is simply reseating a loose connector, there may be no parts cost beyond a service call fee, which typically ranges from $75 to $150. Replacing a faulty high pressure switch generally costs between $50 and $200 for parts plus labor. A failed outdoor unit PCB is the most expensive scenario, with parts and labor potentially ranging from $300 to $700 or more depending on the model.