Author: StringsSG

An aircon chemical overhaul is a more intensive version of chemical cleaning, designed for heavily clogged or underperforming units. It involves complete dismantling of the system and deep-cleaning each component individually using specialized chemicals.

Here are the 9 essential steps followed by professionals during a chemical overhaul:

1. Inspection and Preparation

The process begins with a careful inspection of the aircon unit:

• The technician checks the cooling efficiency, noise levels, airflow, and visible dirt accumulation.
• Protective sheets are laid out to cover your flooring and nearby furniture to prevent any water or chemical splashes during the overhaul.
• The electrical power to the unit is safely turned off.

2. Full Dismantling of the Aircon Unit

In a chemical overhaul, the entire fan coil unit (FCU) is removed from the wall:

• The technician disconnects the electrical connections and drainage pipe.
• The aircon casing, fan blower, and evaporator coil are separated completely from the indoor wall.
• This allows complete access to internal components that are usually unreachable during a standard wash.

🛠️ This step requires experience and should only be done by trained professionals to avoid damage.

3. Disassembly of Components

With the unit taken down, all internal parts are carefully dismantled for separate cleaning:

• Evaporator coil (cools the air)
• Blower wheel (circulates air)
• Drain pan (collects condensation)
• Fan motor and casing

Delicate components such as the PCB (circuit board) are safely covered or removed before chemical treatment.

4. Intensive Chemical Cleaning

Each part is soaked or sprayed with a high-strength chemical solution designed to:

• Break down grease, mold, and hardened dirt
• Eliminate bacteria, dust mites, and allergens
• Restore original airflow and cooling performance

Components are then rinsed thoroughly with water to remove chemical residues and allowed to dry completely.

5. Drainage System Flushing

A clogged drainage pipe is a leading cause of water leakage:

• The technician flushes the drainage system using a pressure pump or manual method to remove clogs.
• Algae, slime, and mineral buildup are cleared, ensuring smooth water flow during operation.

⚠️ Severely blocked pipes may require additional service and charges.

6. Outdoor Condenser Servicing

The outdoor unit, often neglected, is thoroughly cleaned:

• Fins and coils are brushed or vacuumed to remove leaves, dirt, and dust.
• A light water jet may be used to clean the fan and exterior.
• Condenser cleaning improves heat dissipation and reduces the compressor’s workload.

7. Lubrication of Fan Bearings

After cleaning, fan bearings and motor components are lubricated to ensure smooth rotation and reduce friction:

• This helps eliminate humming or squeaky noises.
• Prevents premature wear and tear of moving parts.

8. Refrigerant Gas Level Check

Using pressure gauges, the technician checks the refrigerant gas level:

• If it’s too low, your aircon won’t cool effectively.
• If a leak is suspected, further testing may be required.
• Gas top-up is usually charged separately and done only if needed.

9. Reinstallation and Performance Testing

Once all parts are cleaned and dried:

• The unit is reassembled and securely mounted back on the wall.
• All electrical and drainage connections are reattached.
• A final test is conducted to ensure:
  • Cold air is blowing properly
  • Drainage is smooth
  • The unit is quiet and vibration-free

You’ll immediately notice improved cooling, reduced noise, and cleaner-smelling air.

Why Opt for a Chemical Overhaul Over Regular Servicing?

Chemical Wash	Chemical Overhaul
Partial cleaning	Full disassembly
Keeps unit clean	Restores like-new performance
Less time-consuming	Longer duration (60–90 mins)
For light-to-moderate dirt	For heavily clogged or old units

Aircon chemical washing is a deep-cleaning procedure performed by experienced technicians to restore cooling efficiency, prevent system breakdowns, and extend the lifespan of your unit. Below is a step-by-step guide to how professionals carry out this intensive cleaning service:

1. Inspection and Preparation

Before starting, the technician inspects the aircon unit to assess the cleaning requirements. This helps identify visible dirt buildup, mold presence, and signs of leakage or inefficiency.

Power to the unit is turned off to ensure safety during the procedure.

Furniture, walls, and flooring around the aircon are carefully covered with protective sheets.

2. Disassembly of Components

The technician carefully dismantles key components of the aircon system to gain access to the internal parts that need cleaning:

• Front panel
• Air filters
• Fan coil unit (FCU) cover
• Drain pan

This allows a thorough reach into all areas where dirt and grime accumulate.

3. Chemical Application on Internal Components

A specially formulated chemical solution is applied to dissolve accumulated contaminants such as:

• Mold and mildew
• Dust and dirt
• Bacteria and allergens

These chemicals are safe when handled by professionals and are rinsed off completely to avoid residue.

4. Cleaning the Drainage System

Clogged drainage pipes are a common cause of leaking aircons. The technician will:

• Flush and clean the drainage system
• Remove slime, algae, and debris
• Ensure smooth water flow to prevent future blockages

⚠️ Note: Drainage cleaning may incur additional charges depending on the condition.

5. Outdoor Condenser Cleaning (extra charges may apply)

The outdoor condenser unit, which supports the cooling process, is often overlooked in basic servicing.

• A brush and vacuum are used to clear debris and dust from the condenser fins and fan.
• In some cases, a jet spray is used.
• A clean condenser improves efficiency and reduces power consumption.

6. Monitor and Top-Up Refrigerant Gas (If Needed)

The technician checks the refrigerant gas level to ensure optimal cooling performance:

• If the gas is low, it may cause weak or no cooling.
• A pressure gauge or manifold set is used for accurate readings.
• You will be advised if a gas top-up is necessary.

7. Reassembly and Functional Testing

Once cleaning is complete:

• The unit is reassembled with all parts securely fixed.
• A new or cleaned filter is installed.
• The aircon is powered on and tested for:
  • Cooling performance
  • Unusual noise or vibration
  • Proper airflow and drainage

🌬️ Why Choose a Professional Aircon Chemical Wash?

Getting a chemical wash done by a professional ensures your aircon:

• Runs more efficiently
• Saves electricity
• Improves indoor air quality
• Lasts longer without major repairs

💡 Experts recommend a chemical wash every 6 to 12 months, depending on your usage and environment.

In tropical climates like Singapore, air conditioners are essential for daily comfort. But over time, dust, mold, and grime can build up inside your unit, leading to reduced cooling performance and higher energy bills. A chemical wash is one of the most effective ways to restore your aircon’s efficiency and improve indoor air quality.

While a full chemical overhaul is best left to professionals, a careful DIY aircon chemical wash can help you maintain your unit in between servicing—saving you money and extending its lifespan.

Follow these 8 essential steps to perform your own aircon chemical wash safely and effectively:

1. Safety Precautions

Before you begin, gear up for protection. Wear gloves, goggles, and a face mask to shield yourself from dust and cleaning chemicals. Make sure the area is well-ventilated and that you have all tools and cleaning solutions ready.

2. Turn Off the Power

Always switch off the power supply at the circuit breaker before working on your air conditioner. This is a critical step to prevent electrical shock or short-circuiting during cleaning.

3. Clean the Exterior

Start by wiping down the outer casing of your indoor unit using a damp cloth or sponge. Remove dust, grime, and any loose dirt. Be gentle around delicate fins and avoid pressing too hard on plastic covers or vents.

4. Remove and Clean the Filter

Open the front panel and remove the air filter.

• For light cleaning: Rinse under water or use a handheld vacuum.
• For deeper cleaning: Use a mild detergent or Biget spray (a popular cleaner) and rinse thoroughly in the bathroom.

5. Clean the Evaporator Coils

The evaporator coils inside your aircon absorb heat and are key to cooling. If they’re dirty, your system will struggle to cool effectively.

• Carefully remove the front panel to access the coils.
• Spray a chemical coil cleaner onto the coils and let it sit as instructed (usually 5–10 minutes).
• Rinse off with clean water—avoid spraying directly on wires or electronic parts.

Note: If your evaporator coils are heavily caked with dirt, consider calling a technician for a full chemical overhaul.

6. Clean the Condenser Unit (Outdoor Unit)

Head outside to your condenser unit (usually located on the ledge, balcony, or rooftop).

• Use a hose or low-pressure washer to gently clean the condenser coils and fins.
• Remove any leaves, dust, or debris around the unit to maintain proper airflow.
• Be careful not to bend the delicate aluminum fins.

7. Clear the Drainage System

A clogged drainage pipe can cause leaks or foul smells. Locate the drainpipe and use a brush, pipe cleaner, or a flush of warm water and mild bleach to clear any blockages. Ensure water flows freely out of the drain outlet.

8. Reassemble and Test

Once everything is clean and dry:

• Reinstall the air filter and any panels you removed.
• Restore the power at the breaker.
• Turn on your aircon and let it run for 15–20 minutes.

Observe for strong airflow, no abnormal sounds, and steady cooling. If everything checks out—you’ve just completed a successful DIY chemical wash!

When To Call A Professional

While DIY maintenance can go a long way, some issues require expert attention. Contact a professional if:

• Cooling is still weak after cleaning
• Persistent moldy or chemical odors remain
• Your aircon leaks or makes strange noises
• You haven’t serviced your unit in over a year
• You’re unsure about handling internal components

Final Thoughts

Doing your own aircon chemical wash isn’t as intimidating as it sounds—with the right precautions and step-by-step approach, it’s a rewarding way to keep your unit running efficiently.

Regular maintenance like this can extend your aircon’s lifespan, improve indoor air quality, and help you avoid costly repairs. Just remember: when in doubt, get help from a certified technician.

Aircon units are essential for maintaining a cool and comfortable environment, especially in tropical climates like Singapore. Over time, dust, mold, bacteria, and other contaminants accumulate inside the aircon, reducing its cooling efficiency and air quality. A chemical wash is one of the most effective ways to maintain your aircon.

Whether considering a DIY approach or hiring a professional, understanding the chemicals involved is crucial for proper aircon maintenance. We’re here to help you understand what which chemicals are used in an aircon chemical wash.

Following is the list of 8 commonly used chemicals for aircon cleaning:

1. Alkaline-Based Cleaners

Alkaline-based cleaners are commonly used in aircon chemical washes to remove grease, oils, and organic matter. These cleaners are highly effective for breaking down and loosening dirt and grime that has built up over time.

How they work:

The alkaline cleaner breaks down the oils and grease inside the aircon, making it easier to remove them during the wash. These cleaners are safe for most aircon components and effectively clean parts like the coils, fan blades, and filters.

Benefits:

• Removes oils and grease effectively
• Helps maintain cooling efficiency
• Safe for aircon components like coils and filters

2. Acidic Cleaners

Acidic cleaners dissolve mineral deposits such as rust, limescale, and other hard water buildup that can accumulate on the coils and drain pans. These deposits can block airflow, reduce efficiency, and even damage the aircon system.

How they work:

The acidic properties of the cleaner break down mineral buildup, allowing for easy removal. They are often used on components like the evaporator coils and drain pans to restore proper functionality and prevent further buildup.

Benefits:

• Removes stubborn mineral deposits
• Prevents airflow blockages
• Restores cooling efficiency

3. De-Scalers

De-scalers are specialized solutions designed to remove hardened mineral deposits—especially calcium and magnesium—that build up over time in aircon systems due to hard water exposure. These deposits can obstruct water flow, reduce heat exchange efficiency, and strain system components.

How they work:

De-scalers contain chemical agents that react with limescale and mineral buildup, breaking them down into soluble compounds that can be flushed out easily. They are typically applied to components such as condenser coils, heat exchangers, and internal piping where scale accumulation is most common.

Benefits:

• Dissolves tough limescale and mineral buildup
• Improves heat transfer and energy efficiency
• Prevents corrosion and long-term system wear

4. Rust Inhibitors

Rust inhibitors are protective treatments designed to prevent the formation of rust and corrosion on metal components within the aircon system. Moisture, condensation, and chemical exposure can lead to rust over time, compromising both performance and durability.

How they work:

Rust inhibitors form a thin, invisible barrier on metal surfaces, shielding them from oxygen and moisture—the key ingredients for rust formation. They’re commonly applied to parts like coil fins, drain pans, and metal casings to extend the lifespan of the unit.

Benefits:

• Prevents rust and corrosion on critical components
• Prolongs the life of the aircon system
• Reduces maintenance costs and premature part replacements

5. Biocides and Anti-Mold Chemicals

Mold and bacteria thrive in the moist environment inside your aircon unit, especially in tropical climates like Singapore. Biocides and anti-mold chemicals kill these harmful microorganisms, ensuring that your aircon delivers clean, safe air to your home.

How they work:

Biocides and anti-mold solutions target mold spores and bacteria inside the aircon. The aircon is disinfected using these chemicals, improving indoor air quality and preventing musty smells from circulating through your home.

Benefits:

• It kills mold and bacteria
• Improves air quality
• Prevents foul odors from developing

6. Surfactants (Detergents)

Surfactants, or detergents, are chemicals that lower the surface tension of water, making it easier for water to spread across surfaces and penetrate deep into the dirt. These chemicals are beneficial for breaking down dirt and grime that may have accumulated in the aircon unit.

How they work:

By reducing the surface tension of water, surfactants allow the cleaning solution to break through layers of dirt and grime. They are often used in combination with other chemicals to enhance cleaning effectiveness.

Benefits:

• It breaks down dirt and grime effectively
• Helps to clean hard-to-reach areas
• Ensures a deeper clean

7. Deodorizing Chemicals

Deodorizing chemicals neutralize unpleasant odors caused by mold, bacteria, or accumulated dust. These chemicals leave behind a fresh scent and help improve your home’s overall air quality.

How they work:

Deodorizing agents neutralize the molecules that cause bad odors, eliminating musty, stale, or chemical smells that sometimes come from an aircon unit. These chemicals ensure your aircon blows fresh, clean air after the wash.

Benefits:

• Eliminates bad smells
• Leaves aircon smelling fresh
• Improves the overall air quality in your home

8. Enzyme Cleaners

Enzyme-based cleaners are natural, non-toxic cleaners that use enzymes to break down organic matter such as food, oils, and grease. These cleaners are particularly useful in environments where non-toxic, eco-friendly solutions are preferred.

How they work:

Enzyme cleaners use specific enzymes to target and break down organic debris. They are gentle on the environment and the aircon unit while effectively cleaning components like filters, coils, and fans.

Benefits:

• Eco-friendly and non-toxic
• Breaks down organic matter
• Safe for households with children or pets