What does Error Code U0 mean on a Daikin AC?

Error Code U0 on a Daikin Air Conditioner indicates 'Shortage of Refrigerant'. The system detects that the Electronic Expansion Valve is fully open, but the temperature drop across the coil is insufficient, meaning there is no gas to cool.

Is U0 error dangerous for the AC?

Yes. Running the compressor without refrigerant (which also cools the motor) can cause the compressor to overheat and seize up. The U0 error is a protective shutdown.

How much does it cost to fix Daikin U0 error?

Correcting a U0 error involves finding the leak, brazing it, vacuuming, and refilling gas. Costs typically range from ₹2,400 to ₹4,000 depending on the refrigerant type (R32/R410A).

Daikin AC Error Code U0 | Refrigerant Shortage | Atlas Aircon

Refrigerant Shortage

Daikin Error U0

System Empty.
Your AC has lost its ability to cool.

Symptom

No Cooling

Sign

Ice on Thin Pipe

Fix

Leak Repair + Gas

The “Leakage” Reality

The U0 Error is Daikin’s specific code for “Gas Shortage.” The Electronic Expansion Valve (EEV) opens fully to let gas flow, but the thermistors don’t detect any temperature drop. The system realizes the tank is empty.

Crucial Fact: AC gas does not get “used up” like petrol. If you have a U0 error, you have a physical hole (leak) in your copper pipes. Refilling without fixing the leak is a waste of money.

1 DIY Checks (Confirming U0)

Check Discharge Pipe

Go to the outdoor unit. The thinner copper pipe (Discharge) will likely have white frost or ice on it. This is the classic sign of low gas.

Oil Traces

Look at the flare nuts where the pipes connect to the outdoor unit. If they look wet, oily, or greasy, that’s exactly where the gas leaked out.

Warm Air Output

The indoor fan is running, but the air feels just like a table fan—not cold at all. The compressor might sound louder than usual.

Atlas Aircon Protocol

We don’t just “Top Up”. We Fix.

01.
Nitrogen Leak Test We pump 300-350 PSI of Nitrogen to find the microscopic leak. Without this, the new gas will just leak out again in 2 months.
02.
Vacuuming (Mandatory) We use a 2-stage vacuum pump to remove air and moisture. Air inside an AC causes head pressure issues and compressor failure.
03.
Weighing Scale Charge Inverter ACs need exact gas (e.g., 850g). We use a digital scale to charge the precise amount for maximum cooling efficiency.

Estimated Repair Cost (Atlas Aircon)

Leak Repair: ₹600 – ₹900

Gas Refill (R32): ₹2,400+

Frequently Asked Questions

Why does Daikin have U0 and E4?

They are similar. E4 is “Low Pressure” triggered by a pressure switch. U0 is “Shortage” calculated by temperature sensors and the expansion valve logic. Both mean you need gas.

Can I just top up the gas?

For R32 and R410A, NO. These are blends (or behave like them). Topping up ruins the chemical balance. You must empty the remaining gas, fix the leak, vacuum, and refill fresh gas.

Is U0 caused by dirty filters?

Extremely unlikely. Dirty filters usually cause freezing and “High Pressure” symptoms (if heating). U0 is a very specific logic for lack of refrigerant.

ATLAS AIRCON

Daikin AC Error Code U0