Table of Contents
The short answer
When an AC runs but the room stays warm, the cause is usually on a short list: a setting, a filter choked with dust, a breaker that has tripped, an outdoor unit that cannot get rid of its heat, ice on the indoor coil, or a failed part inside the machine. The first five can be checked in about fifteen minutes, with no tools and without opening anything. The last one cannot.
Work through the checks in the order given here. The early ones take a minute each, and each later one assumes the earlier ones are done. If a check brings the cooling back, you have saved a visit. If none does, you will be able to tell the technician exactly what the unit is doing, which shortens the diagnosis.
Some findings end the checks at once, among them a burning smell, a breaker that trips a second time, and water near anything electrical. Switch the unit off and call. Our AC repair and servicing page sets out how IHR Dream Cleaning diagnoses a fault and confirms the price before any repair starts.
First, work out which kind of system you have
The checks differ a little by system, and one kind of system is not yours to repair at all. A minute spent identifying it saves a wasted call.
| System | How to recognise it | Where the cold comes from |
|---|---|---|
| Wall split | A long unit high on the wall, a remote, and an outdoor unit on the balcony, wall or roof | Refrigerant moving between the indoor and outdoor units |
| Ducted split | Grilles in the ceiling, a thermostat on the wall, an outdoor unit on the roof or in the yard | The same, with the indoor unit hidden above the ceiling |
| Window unit | One box through the wall or window, half inside and half outside | Everything is in the one box |
| Chilled-water fan coil | Ceiling grilles and a wall thermostat, but no outdoor unit of your own | Chilled water piped from the building's central plant |
What counts as a safe check
A safe check uses your eyes, your hands on the controls, and at most a stable step ladder. Lifting the hinged front panel of a wall unit to take out the dust filters is on that list, because the maker's manual gives that job to the owner. Nothing behind the filters is: not the coil, not the fan, not the electrical cover, not the pipes.
The outdoor unit is for looking at, from wherever you can stand safely. Do not climb onto a roof or lean over a balcony rail to reach it, and do not put a hand or a tool through its grille.
Signs that mean stop and switch off
If you find any of these, switch the unit off at the remote and at its wall switch or breaker, leave it off, and call a technician. Running a unit in this state is how a small repair becomes a large one.
- A burning or hot-plastic smell, smoke, or a spark from the unit or its switch.
- A breaker that trips again after one reset.
- Water dripping onto or near a socket, a switch or the electrical side of the unit.
- A grinding, screeching or loud rattling noise that was not there before.
- An outdoor unit that hums or buzzes while its fan stands still.
Check the settings before anything else
Settings come first because they are the quickest thing to rule out and the most annoying thing to pay a visit for. A remote in a child's hand, a new thermostat or a button pressed in the dark is enough to stop the cooling.
The mode: Cool, not Fan, Dry, Auto or Heat
Look at the remote's display or the thermostat. Cool is usually shown as a snowflake. Fan only moves room air and never cools it. Dry, usually a water drop, runs the cooling gently at low fan speed to take moisture out of the air, and will not pull a hot room down. Heat, usually a sun, is fitted to many split units and is easy to select by accident. Auto lets the unit choose for itself. Set the mode to Cool and leave it there for the test.
The set point, the timer and the sleep setting
The unit cools until the room reaches the temperature you set, then rests. If the set point is at or above the room temperature, the fan runs and the compressor does not, which feels exactly like a fault. Set it clearly below the room temperature; 22 to 24 °C is enough for a test.
Choosing the lowest number on the remote does not cool the room any faster. The unit works at full output until the room nears the target either way, and a very low target only makes it run longer.
Look for a timer or a sleep symbol as well. A timer may have switched the unit off on schedule, and on many models the sleep setting lets the room warm by a degree or two through the night.
The remote, its batteries and the wall thermostat
A split unit normally beeps or shows a light when it receives a command. If you press a button and nothing answers, the unit did not hear it. A faint display or missing segments means weak batteries; replace both together, stand in line of sight of the unit and try again.
On a ducted system the control is the wall thermostat. A blank screen usually means flat batteries in the thermostat itself, or no power to the system. Set it to Cool, with the fan on Auto.
Give the unit a fair test
Close the windows and the doors of the room. After any change of mode, and after the power comes back from a cut, the compressor waits a few minutes before it starts. That delay is built in to protect it. After ten to fifteen minutes in Cool, hold your hand in the air leaving the unit. It should feel plainly cold, not just moving.
If you have a kitchen or room thermometer, compare the air going in with the air coming out. As a rough guide, a healthy system delivers air some 8 to 12 degrees colder than the air it takes in. A difference of two or three degrees means it is hardly cooling. Give the technician both numbers; they are more use than 'it feels weak'.
Then check the air: filter, grilles and the outdoor unit
An air conditioner does not make cold. It moves heat: the indoor coil takes heat out of the room air that passes over it, and the outdoor unit throws that heat away outside. Anything that stops air passing over either coil stops the cooling, however healthy the machine is. In Abu Dhabi the usual culprit is dust.
The filter
Switch the unit off first. On a wall split, the front panel lifts from its lower edge and the mesh filters slide out. On a ducted system the filter sits behind the return-air grille, the large grille that draws air in; many of these hinge down on catches. If yours needs tools, or sits higher than a step ladder safely reaches, leave it for the technician. A window unit has its filter behind the front grille.
Hold the filter up to the light. If you cannot see through it, it is the problem or part of it. Rinse it under a cool or lukewarm tap from the clean side, so the water pushes the dust back out the way it came. Shake it off, let it dry completely in the shade, and refit it. Sun and hot water warp the frame, and a filter put back damp soon smells.
Never run the unit with the filters out, even for an afternoon. The dust then lands on the wet coil behind them, where it sets like felt and can only be removed by a proper wash.
Grilles and the path of the air indoors
Check that the supply grilles are open. Some have a lever or a row of blades that closes them, and one closed by accident starves a room. Keep curtains, wardrobes and tall furniture clear of a wall unit's intake, which runs along its top, and of its outlet. On a ducted system, find the return grille and make sure nothing stands against it.
If one room in a ducted home is warm while the rest are fine, the unit is probably healthy and the fault is in the air path to that room: a closed or dust-clogged vent, or a duct that has come loose above the ceiling. That is a job for AC duct cleaning or a duct repair, not for a gas refill.
The outdoor unit
The outdoor unit has to get rid of all the heat taken from the room into air that may already be above 40 °C, and it needs open space to do it. On balconies the usual obstructions are stored boxes, a drying rack, plants grown up against the coil, or a dust cover left on from the winter. On roofs and at ground level it is windblown sand, leaves and plastic bags against the fins.
Look at it while the indoor unit is calling for cooling. The fan should be turning, and the air it throws out should be noticeably hotter than the air around it; that hot air is your room's heat leaving. If the fan turns and the air is no warmer than the day, the compressor is not running. If the unit hums and the fan is still, switch off at once. Do not help the fan round with a stick. The trick is passed around and it is dangerous: a fan that will not start has a failed part, and the compressor behind it is overheating while you try.
With the unit off, move anything that stands against it or in front of its outlet. Leave the fins alone. They are thin aluminium, they bend under a brush or a pressure washer, and bent fins block air as surely as dust does. Washing the outdoor coil properly is part of a service.
Check the power: the wall switch and the breaker
If the indoor unit is completely dead, with no light and no beep, or the indoor fan runs while the outdoor unit stays silent, check the power before assuming the worst.
The AC's own wall switch
In many homes each air conditioner has its own switch on the wall, often high up near the unit and often with a small red light. It is easily knocked off during cleaning or painting, or switched off before a holiday and forgotten. Check that it is on. After a power cut, remember that some units restart by themselves and others wait to be switched on at the remote.
The breaker: reset it once, and only once
Open the distribution board, the panel of switches usually found near the front door or the kitchen. Air conditioners normally have their own breakers, and in a well-labelled board they are marked. A tripped breaker sits in the down position or halfway. Push it fully off, then on. Wait a few minutes for the compressor's start delay, then try the unit.
If the breaker holds, note that it tripped and mention it at the next service; a single trip after a power dip is not unusual. If it trips again, at once or within the hour, leave it off. A breaker trips to stop a cable overheating. A second trip means the fault is still there, in the compressor, a fan motor, the wiring or the breaker itself, and each reset sends current into that fault again. This is the point where the checks end and you make the call.
Which trade you need depends on what trips. If only the AC's breaker goes, start with an AC technician. If the main switch or the earth-leakage breaker for the whole home goes, or other lights flicker when the AC starts, the board and wiring need looking at as well, and that is work for our electrical service. The signs that separate a nuisance trip from a dangerous one are in the guide to tripping breakers, flickering lights and warm sockets.
Ice and water: what they tell you
Both are symptoms and both are useful. Ice tells you the coil is running too cold. Water indoors tells you the drain is not carrying the condensation away.
Ice on the coil or the pipes
The signs are an airflow that fades to almost nothing, air that is no longer cold, white frost visible through the louvres or on the copper pipes, and water dripping once the unit is switched off. The coil ices when its surface drops below freezing, and that happens for one of two reasons: too little warm room air is passing over it, or the refrigerant charge is low. Thaw it first, then find out which.
- Change the mode from Cool to Fan, or switch the unit off if it has no fan mode. Fan mode thaws the coil faster because it blows room air through the ice.
- Put a towel or a shallow tray under the unit. The meltwater should leave by the drain, but a block of ice can overflow the tray inside.
- Leave it until the ice has gone completely. A thin frost clears in under an hour; a solid block can take several hours.
- While it thaws, wash and dry the filters and clear the grilles.
- Start it again in Cool and watch it over the next day or two.
If the ice comes back
Do not chip the ice off or warm it with a hair dryer or hot water; the fins and the plastic tray are easily damaged. If the unit stays clear after the thaw, the dirty filter was the cause. If it ices again with clean filters, stop using it and book a technician. The cause is then inside the machine: a dirty coil, a failing indoor fan, or low refrigerant from a leak. Running an iced unit is hard on the compressor, because refrigerant that should have boiled off in the coil can return to it as liquid.
Water dripping indoors
Cooling wrings water out of the air, and in Abu Dhabi's humid months a single unit produces a great deal of it. The water collects in a tray under the coil and runs away through a drain pipe. A steady drip from that pipe outside, onto the balcony floor or into a drain, is normal and a sign the unit is working.
Water from the indoor unit itself, from a ceiling grille or through the ceiling is not normal. The drain is blocked with dust and slime, or has come loose, or the unit has iced and is thawing. Switch the unit off to stop more water forming, catch what is dripping, and move anything electrical out from under it. Some ducted and cassette units have a safety switch that stops the cooling when the tray is full, so 'not cooling' and 'leaking' are sometimes one fault. Clearing a condensate drain and checking its slope is routine work for a technician. Do not push wire into it or pour chemicals down it.
If the building supplies the cooling
Many Abu Dhabi towers, and some villa communities, are cooled by chilled water from a central plant. In these homes the unit above your ceiling is a fan coil: a fan, a filter and a coil with cold water running through it. There is no compressor and no refrigerant in the apartment, and no outdoor unit that belongs to you.
Your checks are the thermostat (mode, set point, batteries), the filter if the return grille gives you access to it, and the fan coil's breaker or wall switch. If the fan blows but the air is not cold, the likeliest causes are outside your front door or in the valve that lets chilled water into the coil. Ask the security desk or a neighbour whether other homes are warm. If they are, the plant or the supply is down and only the building can restore it.
If you have just moved in, check that the cooling account for the home is active. In some communities chilled water is billed separately by the cooling provider, and a home with no active account may have no supply.
Report the fault to the building management or the facilities team first. Who maintains the fan coil inside the apartment, whether the building, the landlord or the tenant, depends on the building and on your tenancy contract, so read the maintenance clause. Where the fan coil is yours to maintain, a private technician can attend to its fan, filter and drain. Work on the chilled-water valves touches shared pipework, and the building may need to approve it or isolate the supply first.
What each symptom usually points to
Use this table after the checks, to describe the fault. It lists likely causes, not a diagnosis. Several of them look identical from the sofa and are told apart only with instruments.
| What you notice | Likely causes | What you can do |
|---|---|---|
| No light, no beep, nothing | No power to the unit, or a dead remote | Wall switch, breaker (once), batteries |
| Fan blows, air not cold, outdoor unit silent | Wrong mode, no power outdoors, or a failed electrical part or compressor | Mode and set point, then the breaker |
| Air is cool but the flow is weak | Dirty filter, iced coil, closed or blocked grilles | Wash the filter, look for ice |
| Cools at night, struggles by day | Dirty or blocked outdoor unit, low refrigerant, or a unit small for the room | Clear the outdoor unit, clean the filter |
| Cools, then stops with a flashing light | A protection cut-out or a sensor fault | Note the code or the flash pattern |
| Outdoor unit hums, fan still | A failed capacitor or fan motor | Switch off at once |
| Breaker trips when the AC starts | An electrical fault in the unit or its circuit | Reset once, then leave it off |
A word on gas
Low gas is the diagnosis most people expect, and it is one cause among many. The refrigerant in an air conditioner is sealed in and is not used up, so a unit that is truly low has a leak that needs finding. The symptoms overlap heavily: a dirty filter, a dirty outdoor coil and a low charge all give long running times and lukewarm air. Ask for the filter and coils to be checked before anyone connects a gas cylinder, and read when an AC really needs gas and when it does not before you approve a refill.
What to tell the technician
A good description lets the right technician arrive with the right parts. Have these ready when you book or call.
- The system: wall split, ducted split, window unit or chilled-water fan coil, and how many units are affected.
- The brand and rough age, and a photo of the label on the unit. The label carries the model and the refrigerant type.
- What it is doing: no power, air but not cold, weak air, ice, water, noise, smell or a tripping breaker.
- When it started, and whether it is constant or comes and goes. Mention anything that happened first: a power cut, a sandstorm, painting or building work, a long spell switched off.
- What you have already checked and what you found: the state of the filter, whether the outdoor fan turns, any temperatures you measured.
- Any code on the display, or the pattern of any flashing light.
- When the unit was last serviced, and whether it is still under the maker's warranty, which can change how a repair is handled.
- Where the outdoor unit is and how it is reached: balcony, wall bracket or roof hatch. A ladder is brought, but a high or awkward unit should be mentioned at booking.
- In a tower, the building's rules for visiting contractors, so the visit can be registered in advance. The usual steps are in booking a visit in an Abu Dhabi tower.
Before the visit
Clear the space under the indoor unit and around the outdoor one. Leave the unit switched off if it has been grinding, icing or tripping the breaker. If you rent, tell the landlord or agent before you approve a repair; whether the cost is theirs or yours depends on the tenancy contract, and some landlords want their own contractor used. The general method for describing any repair, with the photos worth sending, is in how to get an accurate repair quote.
What the visit involves and what it costs
With IHR the order is fixed. You describe the fault and the type of unit. The technician inspects and diagnoses on site, checking the gas pressure, the filter, the drain line, the thermostat and the electrical connections, so that the fault is identified and not guessed. You are given a quote for parts and labour before any repair or gas top-up begins. The repair is done on the same visit wherever the parts are available, and the unit is run and checked for cooling and airflow before the technician signs the job off. A compressor or a control board may have to be ordered, and then you are given a timeline for the second visit.
Two AC prices are published. Servicing is AED 129 per unit and a split-unit clean is AED 99 per unit, both including VAT. A villa with four split units serviced on one visit is therefore AED 516. What each of those two jobs covers, and how they differ from duct cleaning, is explained in AC cleaning, AC servicing and duct cleaning.
A repair visit starts from AED 99: one technician, the first hour on site and the diagnosis. Parts and gas have no list price, because the same symptom can be a blocked filter or a failed compressor. They are quoted after the diagnosis and before the repair. There is no surcharge for an urgent visit, a Friday or a public holiday. Payment is online by card, from My bookings on this website once the price is confirmed. The per-unit prices are on our price list.
No-cooling calls are prioritised where technician and parts availability allow. We work every day from 8 AM – 8 PM. For a home with no cooling at all, phone +971 52 723 5299 and say so at the start of the call.
Keeping the home bearable while you wait
In summer a home without cooling heats up within hours, and that matters most for babies, older people and anyone who is unwell. If the home cannot be kept comfortable for them, move them to a cooled place for the day. If anyone becomes dizzy, confused or unwell in the heat, treat it as a medical matter and get help; do not wait for the repair.
- Close curtains and blinds on the sunny side, and keep windows shut while it is hotter outside than in.
- Shut the doors of the rooms that still have a working unit, and move the household into them.
- Use fans. A fan does not lower the temperature, but moving air over skin cools people.
- Leave the oven, the tumble dryer and the dishwasher's drying cycle for later. All of them heat the home.
- Drink water, and take a cool shower before bed.
Common questions about an AC that is not cooling
Should I switch the AC off if it is not cooling?
With ice, water indoors or any of the stop signs listed earlier, yes: running it adds damage. If the unit is only cooling weakly and none of those signs is present, it generally does no harm to keep it running at a moderate set point for a day or two while you wait for the visit. Look at it now and then for ice.
Why does it cool at night but not in the afternoon?
Because the afternoon asks more of it. The sun is on the walls and the glass, and the outdoor unit is trying to shed heat into much hotter air. A unit with a dusty outdoor coil, a slightly low charge or a blocked filter has no reserve left for those hours. Clean filters, a clear outdoor unit and a service usually restore the margin. If they do not, the unit may be small for the room, especially a room with large west-facing glass.
The display shows a code or a flashing light. What does it mean?
Most modern units report a detected fault as a code or a pattern of flashes. The meaning is specific to the maker and the model, so write down exactly what you see, or film it, and pass it on. Switching the unit off at its breaker for five minutes sometimes clears a one-off error. If the code returns, do not keep resetting it; the unit is protecting itself from something.
How often should the filters be cleaned?
Check them once a month as a habit, and after every sandstorm. In homes near open desert, main roads or building sites, and in homes with pets, look every couple of weeks. Filter cleaning is the owner's part of the upkeep. The coils, the drain and the electrical checks are the technician's part, at a service every six to twelve months in this climate, ideally before the summer.
Who pays for the repair in a rented home?
It depends on your tenancy contract. Contracts differ on which repairs fall to the landlord and which to the tenant, and buildings differ on what their own maintenance team covers. Read the maintenance clause and ask the landlord or agent in writing before approving anything costly. If you need paperwork for a claim, a tax invoice is available on request for any booking.
When the checks do not fix it
If the settings are right, the filters are clean, the power is on and the outdoor unit is clear, you have done everything that can safely be done without opening the machine. What is left needs instruments and a trained hand.
Our AC repair and servicing page lists what the service covers for split, window and central systems. To arrange a visit, book online and describe the fault using the list above, or phone if there is no cooling at all. The price is confirmed with you before any repair begins.
