Daikin Mini Split Error Code H4: How to Fix It

Q: What does Daikin error code H4 mean?

Daikin error code H4 indicates a low pressure switch fault. The system's low pressure switch has detected abnormally low refrigerant pressure in the system.

Q: Can I fix Daikin error code H4 myself?

Basic troubleshooting like cleaning filters and coils can be done yourself. However, if the issue is a refrigerant leak or a faulty low pressure switch, professional service is required due to EPA regulations and the need for specialized tools.

Q: What causes low pressure in a mini split?

Common causes include refrigerant leaks, dirty air filters or coils, a faulty low pressure switch, low outdoor temperature, or a restricted expansion valve.

Q: How do I reset Daikin error code H4?

Turn off the system at the breaker for at least 5 minutes, then turn it back on. If the issue is resolved, the error should clear. If it reappears, the underlying problem needs to be fixed.

Q: Where is the low pressure switch on a Daikin mini split?

The low pressure switch is typically located on the outdoor unit, often near the service valve or accumulator. Consult your unit's service manual for exact location.

Abstract

Error code H4 on your Daikin mini split indicates a low pressure switch fault. This means the system has detected abnormally low refrigerant pressure, which can be caused by a refrigerant leak, a clogged filter or coil, a faulty low pressure switch, or an issue with the outdoor unit. The system will stop operating to prevent damage. Follow the steps below to diagnose and fix the problem.