It’s one of the most frustrating aircon problems you can have. You hear the indoor unit turn on, the fan is blowing air, but the air just isn’t getting cold.
You go outside to check the condenser unit, and you notice the big fan on top is spinning, but that familiar, powerful hum from deep inside the machine is missing. That’s the sound of the compressor.
And if the aircon compressor not working, your aircon is just a fan.
The compressor is the heart of your air conditioning system. Its job is to pump the special gas (refrigerant) through the copper pipes between your indoor and outdoor units. This pumping action is what moves heat from inside your home to the outside. Without it, no cooling can happen.
A dead compressor sounds like a huge, expensive problem, and sometimes it is. But very often, the compressor itself is fine! It has simply stopped working because another, smaller part has failed.
As technicians at Vedha Aircon, this is a problem we solve all the time. Here’s our checklist of common reasons why your compressor might have stopped working.
1. Simple Electrical Issues (The Most Common Culprits)
Before we panic, we always check the simple electrical parts first. More often than not, one of these is the culprit.
- A Bad Capacitor: This is the number one reason a compressor won’t start. The capacitor is a small cylinder-shaped part that acts like a battery, giving the compressor a strong jolt of energy to get started. When it fails, the compressor might try to start, make a “buzz” or “hum” sound, but won’t have enough power to kick on. While it’s a common DIY replacement, a capacitor can hold a dangerous electrical charge even when the power is off, so it’s safest to let a professional handle it.
- A Worn-Out Contactor: The contactor is an electrical switch that tells the compressor and fan motor when to turn on and off. Over years of use, the connection points on the switch can become pitted or worn out, preventing power from reaching the compressor.
- A Failed Hard Start Kit: If your aircon is a bit older, a technician might have installed a “hard start kit” to help the aging compressor turn on. These kits can also fail, and sometimes they can even blow apart spectacularly.
2. Overheating Problems (The “Working Too Hard” Issues)
Your compressor generates a lot of heat while it’s running. If it can’t get rid of that heat, a built-in safety switch called a thermal overload will shut it down to prevent it from burning out. This is very common on Singapore’s hottest days.
- Dirty Outdoor Coils: Your outdoor unit gets rid of heat through the metal fins on its sides. Over time, these fins get clogged with dirt, dust, and fluff. When this happens, the unit can’t “breathe” properly. The heat gets trapped, pressure builds up, and the compressor overheats and shuts off.
- A Failing Outdoor Fan Motor: The big fan on top of your outdoor unit has a critical job: to pull air through the coils and blow the heat away. If this fan motor is dead or spinning too slowly (often due to its own bad capacitor or worn bearings), heat isn’t removed. The compressor will quickly overheat and go into protection mode.
3. System-Wide Problems (A Sign of Something Deeper)
Sometimes, the compressor stops because of a problem elsewhere in the system. These are clever safety features designed to prevent bigger disasters.
- Clogged Water Drain Pipe: Your indoor fancoil unit removes a lot of humidity from the air, which collects as water and flows out through a drain pipe. If this pipe gets clogged with slime and gunk, the water will back up. A small safety device called a float switch will detect the high water level and cut power to the compressor to prevent the water from overflowing and damaging your ceiling or walls. The unit might start working again after resting for a while, because the water has had time to slowly drain away.
- Low on Aircon Gas (Refrigerant Leak): If your system has a slow gas leak, the pressure inside can drop too low. A safety sensor will detect this low pressure and shut the compressor off to protect it from damage.
- The Compressor Itself Has Failed: This is the one we hope it isn’t, but it does happen. After many years of service, or due to a major electrical burnout, the compressor can fail internally. If your unit has had multiple compressors replaced in just a few years, it’s a major red flag that there is a serious underlying problem with the installation, like acid left in the pipes from a previous failure.
Don’t Panic! Here’s How Vedha Can Help.
Seeing your compressor refuse to start can be stressful, but as you can see, the cause is often a much smaller and more affordable fix.
When you call Vedha Aircon, you get experienced technicians who do proper detective work.
- We start with the simple things, safely testing the capacitor and contactor.
- We check for overheating issues, inspecting your outdoor coils and fan motor.
- We look at the whole system, checking your indoor drain line to ensure it isn’t clogged.
- We only check refrigerant levels when necessary, so we don’t waste your gas or money.
We’ll find the real problem, explain it to you clearly, and give you a fair, upfront price for the repair. No games, no hidden costs.
If your aircon is blowing warm air, don’t sweat it. Call the pros at Vedha Construction at 96540044 or send us an email to get it sorted out quickly.
Vedha Aircon: Reliable Aircon Compressor Repair Services, Fair Prices, No Fuss.
We specialize in Aircon installation, repair, and service. We have all type & model of recon compressor, full set & fancoil. Our technicians are highly proficient in their respective field and repairs and fixes aircon of various brands.
