Your AC May Be Running Non-Stop Because of a Small Sensor Fault
Most people assume that when an air-conditioner runs non-stop, the problem must be serious.
They immediately think:
- Compressor failure
- Gas leak
- PCB board issue
- Major electrical fault
But in many Singapore homes and commercial buildings, the real cause is much smaller.
👉 A faulty temperature sensor.
And this small component can quietly create a big problem.
What Does the AC Sensor Actually Do?
Inside every air-conditioning unit, there is a temperature sensor (thermistor). Its job is simple but critical:
It measures the temperature of:
- The room air
- The evaporator coil
Then it sends that data to the control board.
When the room reaches the set temperature (for example, 24°C), the sensor signals the system to reduce or stop compressor operation.
This is how your AC maintains comfort while saving energy.
But when the sensor fails — everything changes.
What Happens When the Sensor Becomes Faulty?
A sensor can fail due to:
- Aging and wear
- Dust accumulation
- Loose mounting from the coil
- Wiring damage
- Moisture exposure
- Corrosion in humid environments like Singapore
When this happens, the sensor may:
- Read the wrong temperature
- Send unstable signals
- Fail to detect actual cooling
So even if the room is already cold, the AC “thinks” it is still hot.
The result?
❄️ Compressor keeps running non-stop
⚡ Electricity bill increases
🧊 Ice forms on the coil
💧 Water leakage may start
🔥 Compressor lifespan reduces
All because of one small sensor.
Why Continuous Running Is Dangerous
Many customers say:
“It’s okay, at least it’s cooling.”
But continuous compressor operation creates hidden damage.
- Higher Electricity Consumption
A non-stop running compressor consumes significant power. Over one month, this can increase your utility bill noticeably.
- Coil Icing
If the evaporator temperature sensor fails, the coil may drop below freezing. Ice forms, blocking airflow.
Restricted airflow causes:
- Poor cooling
- Water dripping
- System strain
- Compressor Overheating
When the compressor never cycles off, it experiences constant stress. Over time, motor windings weaken.
Replacing a sensor is affordable.
Replacing a compressor is not.
Common Warning Signs You Should Not Ignore
Look for these symptoms:
- AC never reaches the set temperature
- Room feels too cold even at normal settings
- AC runs continuously without stopping
- Ice forming on indoor unit
- Unusual water leakage
- Higher-than-usual electricity bill
If you notice two or more of these signs, a sensor issue is very possible.
Why DIY Guesswork Makes It Worse
Some building owners try quick fixes:
- Gas top-up without checking
- Resetting thermostat repeatedly
- Changing PCB unnecessarily
- Ignoring the issue
This can lead to:
- Wasted money
- Misdiagnosis
- Bigger repair cost later
Professional diagnosis is important because sensor faults can look similar to gas or PCB issues.
What a Proper Professional Check Should Include
A proper technical inspection should involve:
Electrical Testing
- Measuring sensor resistance value
- Comparing readings with manufacturer specifications
- Checking wiring continuity
- Inspecting PCB signal input
Refrigerant & Pressure Check
- Measuring suction pressure
- Confirming refrigerant charge
- Checking airflow performance
Thermal Evaluation
- Verifying coil temperature behavior
- Checking compressor cycling pattern
- Ensuring thermostat accuracy
Only after proper diagnosis should replacement be done.
Why This Problem Is Common in Singapore
Singapore’s environment makes sensor issues more frequent because of:
- High humidity
- Constant AC usage
- Dust accumulation in coils
- Condensation exposure
Over time, moisture and dust affect sensor accuracy.
That is why preventive servicing is critical — not just gas top-up.
The Cost Comparison That Matters
Let’s compare:
Sensor replacement → Small repair cost
Compressor replacement → Major repair cost
Full system damage → Even higher expense
A small unchecked issue can become a large financial problem.
Early detection saves money.
Final Advice for Building Owners & Homeowners
If your AC is running non-stop, don’t assume it’s normal.
Continuous operation is not efficiency.
It’s a warning sign.
A small sensor fault can silently:
- Increase your bills
- Reduce system lifespan
- Lead to compressor failure
Professional inspection today can prevent major breakdown tomorrow.
Don’t Let a Small Sensor Destroy Your System
If your aircon is not cycling properly, get it checked before damage spreads.
📞 Call / WhatsApp: +65 8151 8857
🌐 Website: www.aotrinitysg.com.com
Alpha & Omega Trinity Pte Ltd
Professional Aircon Diagnosis & Repair in Singapore
Small component. Big impact.
Act early. Save later.
