AC Compressor Not Working — Signs, Causes, and Repair Cost in Lahore
The compressor is the most important and most expensive component in your AC system. When it fails, the AC cannot cool at all. In our 10 years of AC repair in Lahore, compressor problems account for roughly 15 to 20 per cent of all major repair jobs we handle — and they are almost always preventable.
This guide explains how to tell if your compressor has failed, the most common causes in Lahore, and what your repair options realistically are.
Signs that your compressor may have failed
The outdoor unit does not run at all
When you switch the AC on, the indoor unit starts — fan runs, air comes out — but the outdoor unit is completely silent. You can check this by going outside and listening. If the outdoor unit’s fan is not spinning and there is no sound of a compressor running, either the compressor has failed or there is an electrical fault preventing it from starting.
The outdoor unit tries to start, makes a clicking or humming sound, then stops
This is one of the most classic signs of a failing compressor or a failed start capacitor. The motor tries to start, cannot, and the thermal overload protection cuts it off before it overheats.
The AC runs but produces no cooling whatsoever
Not reduced cooling — zero cooling. Room-temperature air blowing from the indoor unit with a completely silent outdoor unit is a clear indicator the compressor is not running.
The circuit breaker trips every time the AC is switched on
A short-circuit in the compressor motor windings can cause the MCB to trip immediately. If this is happening, switch the AC off and do not keep trying to reset the breaker — you risk damaging other components.
Common causes of compressor failure in Lahore
Running the AC with low refrigerant gas for extended periods
This is the leading cause of premature compressor failure in Lahore. When gas levels are low, the compressor runs without adequate lubrication (refrigerant carries lubricating oil through the system) and without proper cooling (gas returning to the compressor keeps it cool). Running in this condition for weeks or months causes the compressor to overheat and eventually seize.
This is why we always say: if your AC is not cooling well, do not just run it harder. Get the gas checked before it damages the compressor.
Voltage fluctuations and power surges
Lahore’s power supply is notoriously unstable. Voltage fluctuations — especially sudden spikes when WAPDA power is restored after a load-shedding cut — cause electrical stress on compressor motor windings. Over time, this weakens the winding insulation until a winding failure occurs.
A good voltage stabiliser (1,500 VA or higher for a 1.5-ton AC) is the single most effective protection against voltage-related compressor damage.
Overheating from blocked outdoor unit airflow
When the outdoor unit is boxed in, covered in dust, or has restricted airflow, the compressor overheats during operation. Most compressors have a thermal overload switch that cuts them off when they overheat — but repeated thermal cycling degrades the windings and bearings over time.
Age
Compressors in well-maintained ACs in Lahore typically last 8 to 12 years. In poorly maintained units running in harsh conditions, 5 to 7 years is more realistic. If your AC is 10 or more years old and the compressor has failed, the economics of replacement versus repair need to be considered carefully.
Diagnosing the compressor vs other components
Before concluding that the compressor has failed, a technician should rule out two simpler and cheaper causes:
Start capacitor failure: The start capacitor helps the compressor motor start up. When it fails, the compressor cannot start — symptoms are identical to compressor failure. Capacitor replacement costs Rs. 800 to Rs. 2,000 and takes 15 minutes. Always check this first.
Contactor or relay failure: The contactor is an electrical switch that sends power to the compressor. If it fails, the compressor gets no power. Another cheap fix if that is the actual cause.
A competent technician will check capacitor and contactor before opening up the compressor circuit. If you are quoted for a compressor replacement before these simpler components are checked, ask specifically whether the capacitor was tested.
What does AC compressor repair or replacement cost in Lahore?
- Start capacitor replacement: Rs. 800 to Rs. 2,000
- Contactor replacement: Rs. 500 to Rs. 1,500
- Compressor rewinding (motor winding repair): Rs. 3,500 to Rs. 6,000 — viable if the mechanical parts of the compressor are intact
- New compressor replacement: Rs. 4,500 to Rs. 12,000 depending on brand and tonnage
For a newer AC (under 5 years old), compressor repair or replacement is almost always worth it. For an AC that is 10 or more years old with other signs of wear, replacing the entire unit may give better long-term value.
Should you repair or replace?
Use this simple rule of thumb: if the repair cost is more than 50 per cent of the price of a new AC of the same size, replacing is the better financial decision — especially if the existing unit is more than 8 years old.
If the compressor cost is under 30 to 40 per cent of a replacement unit’s price, repair makes sense — provided the rest of the AC is in good condition.
How to protect your compressor going forward
- Use a good voltage stabiliser — Rs. 3,000 to Rs. 5,000 for a quality unit is cheap insurance for a compressor that costs three times as much to replace.
- Service your AC once a year and get gas pressure checked every 2 years.
- Make sure the outdoor unit has clear airflow and is cleaned regularly.
For compressor diagnosis and repair across all areas of Lahore, call or WhatsApp Xpert AC Service at 0329-6912017.
We will diagnose the actual cause before recommending any repair, and give you a transparent price upfront.