Daikin AC Error Code E4 — What It Means & How to Fix It

What Does This Error Mean?

E4 on a Daikin AC means the high pressure switch on the outdoor unit has tripped. The refrigerant pressure in the discharge circuit has exceeded the maximum safe level. Daikin stops the compressor immediately to protect it from mechanical damage.

Affected Models

Daikin FTKF Series
Daikin FTKG Series
Daikin ATKF Series
Daikin Inverter Split AC (all models)

Common Causes

Outdoor heat exchanger coil blocked — cannot reject heat, pressure rises
Outdoor fan motor or capacitor failed — no airflow over the condenser
Refrigerant overcharge — excess gas creates pressure beyond operating limits
High pressure switch faulty — tripping at normal pressure readings
Non-condensable gas (air or nitrogen) in the refrigerant circuit
Ambient temperature above the rated operating limit of the outdoor unit

How to Fix It

Switch off and inspect the outdoor unit for blockages.

Confirm all sides of the outdoor unit are clear of obstructions. Daikin outdoor units need 60 cm clearance at the discharge (front/top) and 20 cm at the sides.
Check the outdoor fan is running when the compressor is on.

A running compressor with a stationary outdoor fan will cause E4 within minutes. If the fan is not spinning, a capacitor replacement is usually the fix.
Clean the outdoor condenser coil.

Rinse the coil fins with low-pressure water (circuit breaker off first) spraying from inside outward. Allow 30 minutes to dry before restarting.
Call Daikin service if E4 returns after one restart.

The technician will measure high-side pressure with manifold gauges. If overcharge is confirmed, excess refrigerant must be recovered before the AC is safe to run.

When to Call a Professional

E4 requires a licensed technician. Daikin India customer care: 1800-103-3666. Do not restart repeatedly — high pressure events stress compressor discharge valves.

Frequently Asked Questions

What is the difference between E3 and E4 on Daikin AC?

E3 on Daikin means the discharge pipe temperature is too high — a temperature fault. E4 means the high pressure switch has tripped — a pressure fault. Both relate to the high side of the refrigerant system and often have the same causes (blocked coil, low refrigerant, fan fault), but they are measured differently: E3 by a thermistor, E4 by a pressure switch.

Can E4 on Daikin AC damage the compressor?

The high pressure switch protection is specifically designed to prevent compressor damage. If the switch trips before pressure reaches destructive levels, the compressor is protected. However, repeatedly restarting and retripping the switch eventually stresses the discharge valves and can shorten compressor life.