What does Error Code E1 mean on a Blue Star AC?

Error Code E1 on a Blue Star Air Conditioner indicates a 'Room Temperature Sensor Fault'. This usually means the black-tipped sensor measuring room air temperature is Open (wire cut) or Short (damaged).

What is the resistance value of Blue Star AC sensor?

Many Blue Star Inverter ACs use a **15k Ohm** or **20k Ohm** NTC sensor for the Room Temperature at 25°C. It is crucial to measure the old sensor or check the service manual, as using a standard 10k sensor may cause cooling errors.

Can I run the AC with E1 error?

No. The AC relies on this sensor to regulate the compressor speed. Without it, the system enters a safety lockout mode to prevent over-cooling or freezing.

Technician Note

Always isolate power before inspecting high-voltage components.

Blue Star AC Error Code E1 | Room Sensor Fault | Atlas Aircon

Sensor Wire Break

Blue Star Error E1

Room Sensor Failure.
Your AC has lost its sense of temperature.

#1 Cause

Rat Bite

Check

Loose Jack

Fix

Replace Sensor

The “Blind” AC Problem

The E1 Error refers to the Room Temperature Sensor. It is the small black probe usually located in front of the air filters. Its job is to tell the PCB the current temperature of your room.

“Open” or “Short”: This means the electrical circuit is broken. The most common reason in Indian households is that a rat has chewed through the thin wires, or the sensor itself has failed due to moisture/age.

1 DIY Visual Checks

Rat Damage Inspection

Open the front grill. Look at the right side where the wires go into the PCB box. Are the thin black wires chewed? This accounts for 90% of E1 errors.

Loose Connector

If the AC was just serviced or moved, the sensor plug (jack) on the PCB might have come loose. A gentle push might fix it.

Moisture Damage

If water is dripping inside the unit, it can soak the sensor head, causing erratic resistance readings (Short Circuit).

Atlas Aircon Repair Protocol

How we fix the E1 Fault:

01.
Resistance Check (Ohms) We unplug the sensor and use a multimeter. Blue Star ACs often use **15kΩ or 20kΩ** sensors. We verify the value against the service manual.
02.
Wire Repair vs Replace If rats cut the wire in the middle, we can rejoin and solder it. If the cut is too close to the sensor head or jack, we replace the whole unit.
03.
PCB Jack Inspection We check the PCB connector for rust or carbon. Sometimes the sensor is fine, but the PCB port is dirty.

Estimated Repair Cost (Atlas Aircon)

Wire Repair: ₹350 – ₹500

New Sensor: ₹650 – ₹950

Frequently Asked Questions

Can I buy any sensor from the market?

**No.** Different brands use different resistance values. While Voltas uses 10k, Blue Star often uses **15k or 20k**. Using the wrong one will cause the AC to read the temperature incorrectly.

Is E1 the same as E2 or E6?

No. **E1** is the Room Air Sensor. **E2** is typically the Indoor Coil Sensor. **E6** is often the Outdoor Sensor or Communication error. Each requires a different fix.

Can I bypass the sensor?

No. The PCB logic requires a valid resistance reading to operate. You cannot just join the two wires together (Short Circuit) or leave them open; both will trigger the E1 error.