AC Troubleshooting &
Diagnostic Guide
Click your symptom. Our diagnostic engine identifies whether it's a free DIY fix or needs a certified technician — saving you ₹500–2,000 in unnecessary service calls.
Stop AC Immediately If...
- •You smell burning plastic or electrical odour
- •You hear a loud hissing or bubbling sound
- •You see sparks or smoke from any unit
- •Water is dripping near electrical wiring
Safe to Try Yourself
- •Cleaning or replacing the air filter
- •Clearing a blocked drain pipe
- •Resetting the MCB / circuit breaker
- •Replacing remote control batteries
Stabilizer Checks
- •A faulty stabilizer is a common cause of compressor damage
- •Check stabilizer LED indicators for high/low voltage
- •Listen for excessive relay clicking from the stabilizer
- •Verify stabilizer output reads 200V–240V before AC starts
Always Call a Technician
- •Refrigerant (gas) refill or leak repair
- •PCB or compressor replacement
- •Any internal electrical work
- •Chemical coil wash and deep service
Symptom Checker: What's Wrong with Your AC?
Click your symptom below. Our diagnostic engine will tell you if it's a DIY fix or needs a technician.
Common Error Codes for LG, Daikin, and Voltas ACs
Decode your AC's blinking lights. Find your brand and error code to understand the fault and estimated repair cost.
| Brand | Code | Meaning | Severity | Recommended Action |
|---|---|---|---|---|
| LG | CH01 | Indoor room temperature sensor fault | Medium | Replace NTC sensor — ₹300–500 |
| LG | CH02 | Indoor coil temperature sensor fault | Medium | Replace coil sensor — ₹300–500 |
| LG | CH05 | Communication error (indoor ↔ outdoor) | High | Check wiring, may need PCB replacement |
| LG | CH10 | Outdoor unit EEPROM error | High | Outdoor PCB replacement needed |
| LG | CH38 | Outdoor temperature sensor fault | Medium | Replace outdoor NTC sensor |
| Daikin | A1 | Indoor PCB fault | High | PCB replacement — ₹2,000–5,000 |
| Daikin | A5 | Freeze protection / high pressure | High | Check refrigerant level and airflow |
| Daikin | C4 | Heat exchanger sensor fault | Medium | Replace thermistor sensor |
| Daikin | E1 | Outdoor PCB fault | High | Outdoor PCB replacement needed |
| Daikin | E7 | Outdoor fan motor fault | High | Fan motor replacement — ₹1,500–3,000 |
| Voltas | E1 | Indoor ambient sensor open/short | Medium | Replace room temperature sensor |
| Voltas | E2 | Indoor coil sensor open/short | Medium | Replace coil temperature sensor |
| Voltas | E4 | Outdoor ambient sensor fault | Medium | Replace outdoor sensor |
| Voltas | P4 | Compressor discharge temperature high | High | Stop AC immediately — check refrigerant and compressor |
| Samsung | E1 | Indoor temperature sensor error | Medium | Sensor replacement — ₹400–600 |
| Samsung | E2 | Indoor coil sensor error | Medium | Sensor replacement — ₹400–600 |
| Samsung | E4 | High pressure protection | High | Check refrigerant and outdoor unit |
| Hitachi | E1 | Indoor PCB error | High | PCB replacement needed |
| Hitachi | E9 | Outdoor unit communication error | High | Check inter-unit wiring |
| Blue Star | E1 | Room temperature sensor fault | Medium | Replace NTC sensor |
| Blue Star | E6 | Communication error | High | Check wiring between units |
Error codes may vary by model year. Always cross-check with your AC's user manual or brand service app.
When to DIY and When to Call an Expert
Save money on simple fixes. Know when to stop and call a certified HVAC technician.
Safe to DIY
No tools or expertise needed
Clean air filter
10 min · Easy
Clear blocked drain pipe
20 min · Easy
Power cycle / reset AC
5 min · Easy
Replace remote batteries
2 min · Easy
Clean outdoor unit fins
30 min · Medium
Check MCB / circuit breaker
5 min · Easy
Call a Technician
Risk of injury or further damage
Refrigerant (gas) refill
Toxic gas — certified only
PCB / control board replacement
High voltage — expert only
Compressor replacement
Requires vacuum pump & tools
Capacitor replacement
Stored charge — shock risk
Deep coil cleaning (chemical wash)
Chemicals + disassembly
Fan motor replacement
Wiring expertise needed
Safety First Rule
Never open the outdoor unit or touch electrical components while the AC is powered on. Always turn off the MCB before any inspection. If you smell burning or see sparks, turn off the main power and call a technician immediately.
The two products that make every tip work better
A 5-star inverter AC + BLDC fan is the single most impactful combo for cutting your electricity bill in India.
LG 1.5T 5★ Dual Inverter
AI Cooling · ISEER 5.25
Pro tip: Run the LG AC at 26°C with the Atomberg BLDC fan — the fan's wind-chill effect makes 26°C feel like 24°C, cutting your bill by ~30% vs running AC alone at 24°C.
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Frequently Asked Questions
Quick answers to the most common AC troubleshooting questions.