The Customer's Situation
Encik Danial works from home in his Putrajaya condo. His home office Samsung 1.5HP aircond had been frustrating him for weeks — he'd set it to 24°C but the room never felt cold enough. He measured with a separate thermometer: 28°C. Yet the aircond's display confidently showed 23°C. The compressor would kick in for 5 minutes, then shut off for 10 minutes, repeating this cycle endlessly.
He'd already called another technician who checked the gas level (normal) and cleaned the unit (already recently cleaned). That technician shrugged and said "maybe the unit is getting old." The Samsung was only 3 years old.
Encik Danial found our blog on thermostat sensor problems and recognised his exact symptoms. He called us suspecting the sensor.
Our Diagnosis
Technician Amin arrived with a calibrated thermometer and confirmed: room temperature was 28.2°C. The Samsung's display showed 23.1°C — a 5°C discrepancy. He accessed the indoor unit's thermistor and tested it with a multimeter: the resistance reading corresponded to approximately 23°C, confirming the sensor was reading 5 degrees too low.
The aircond's PCB was making correct decisions based on incorrect data. It "thought" the room was already at 23°C (below the 24°C target), so it kept cycling the compressor off. The aircond was working perfectly — it was just being lied to by its own sensor.
The Fix
Amin replaced the faulty 10kΩ NTC thermistor with a new compatible unit. After installation, the sensor read 28.0°C — within 0.5°C of the calibrated thermometer. The PCB immediately responded: compressor engaged at full power and stayed on, driving the room temperature down steadily.
Within 15 minutes, the room hit 24°C. The compressor then modulated to low power (Samsung inverter technology) and maintained the temperature perfectly. Exactly how it should have been working all along.
Results
- Temperature accuracy: Sensor now reads within 0.5°C of actual
- Room cooling: Reaches set temperature in 15 minutes (was never reaching it before)
- Compressor cycling: Normal sustained cooling instead of short on/off cycles
- Work comfort: Encik Danial's home office finally comfortable for full workdays
Pricing
- Diagnosis: RM50
- 10kΩ NTC thermistor: RM20
- Installation + calibration: RM60
- Total: RM130
Issues Identified
- Samsung 1.5HP aircond set to 24°C but room stays at 27-28°C
- Unit cycles compressor on/off every 5 minutes as if room is already cold
- Gas level confirmed normal by previous technician
- Filters and coils recently cleaned — not the issue
- Room temperature display on unit shows 23°C when actual room temp is 28°C
Work Completed
- Diagnosed faulty room temperature thermistor — reading 5°C lower than actual
- Removed defective thermistor from indoor unit
- Installed new compatible thermistor (10kΩ NTC type)
- Calibrated and tested — sensor now reading within 0.5°C of actual room temperature
- Aircond compressor running sustained cycles and cooling room to 24°C properly
- Full 20-minute performance test — room reached set temperature in 15 minutes
Customer Feedback
"The previous technician couldn't figure it out. Amin diagnosed it in 10 minutes by simply comparing a thermometer to the display. A RM20 sensor was the whole problem. Weeks of discomfort fixed for RM130. I'm impressed by the diagnostic skill — it's not just about cleaning coils."
— Encik Danial, Putrajaya
Aircond Not Reaching Temperature?
Could be a simple RM20 sensor. Professional diagnosis finds the real problem fast.
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