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.

1. Higher Electricity Consumption

A non-stop running compressor consumes significant power. Over one month, this can increase your utility bill noticeably.

2. 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

3. 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 costCompressor replacement → Major repair costFull 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 LtdProfessional Aircon Diagnosis & Repair in Singapore

Small component. Big impact.Act early. Save later.