F1
Blue Star Split AC
Severity: ModerateWhat Does This Error Mean?
F1 on a Blue Star AC means the indoor ambient temperature sensor has a fault. This sensor reads room temperature so the AC can control cooling to reach the target temperature you set. A failed or disconnected sensor triggers F1 and the AC stops operating.
Affected Models
- Blue Star Inverter Split AC (all capacities)
- Blue Star 3 Star Inverter
- Blue Star 5 Star Inverter
- Blue Star FS Series
- Blue Star IC Series Inverter
Common Causes
- Indoor ambient thermistor failed — resistance outside the normal operating range
- Thermistor connector loose at the indoor PCB
- Thermistor wire damaged during installation or annual servicing
- Dust accumulation on the thermistor probe causing incorrect temperature readings
- Indoor PCB fault causing incorrect thermistor signal interpretation
How to Fix It
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Switch off the AC at the remote and main switch. Wait 5 minutes and restart.
If F1 clears and does not return, it was a transient sensor error. Monitor over the next few cycles.
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Clean the air filter and front panel grille.
The ambient thermistor reads room air drawn through the front panel. Clean the panel and filter to ensure unrestricted airflow past the sensor.
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Call Blue Star service (1800-209-1177) if F1 persists.
Have your model number ready — it is on a sticker on the right side panel of the indoor unit.
When to Call a Professional
F1 requires a Blue Star authorised technician. Blue Star service helpline: 1800-209-1177. A technician will test the ambient thermistor resistance and replace the sensor if it reads outside specification.
Frequently Asked Questions
How much does Blue Star F1 repair cost in India?
An indoor ambient thermistor typically costs Rs 200–500 for the part. With the Blue Star service visit charge and labour, total repair is usually Rs 1,000–2,000. Under the 1-year comprehensive warranty, parts and labour are covered at no charge.