E4
Daikin Low-Pressure Protection

Daikin unit stops with E4; often during heating mode

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Refrigerant leak, Blocked indoor coil or filter, Expansion valve malfunction, Frost/ice buildup on outdoor coil

How to Fix / Troubleshooting

Safety first: Do not attempt to add refrigerant yourself. Turn off power before cleaning filters or coils.

User steps:

  • Clean indoor filters and ensure indoor airflow is not restricted.
  • Check outdoor unit for heavy ice buildup; allow unit to defrost by turning it off if necessary.

Technician tasks:

  • Leak-check the system and repair any leaks.
  • Verify operation of the electronic expansion valve (EEV) and replace if stuck.
  • Recharge refrigerant to the correct Daikin-specified amount.
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Repair Difficulty

Professional Required 5/5

Required Part

Refrigerant Circuit / Electronic Expansion Valve
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