Air conditioning repair in London
A unit that has simply stopped cooling. One that is dripping water onto the carpet. One that trips the electrics the moment it switches on. Whatever the symptom, the actual cause is rarely obvious just by looking at the box on the wall — it could be the refrigerant, the drainage, the electrics or the unit itself. Ninja Plumbers finds the real fault first, then prices the repair, so you are never paying for a guess.
- F-Gas certified for refrigerant work
- Fully insured, DBS-checked engineers
- Price agreed before work starts
- Workmanship guaranteed
Monday – Sunday, 7:00 AM – 10:00 PM · Out-of-hours emergency? Call 020 3576 5825
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What this includes
- Units not cooling, or barely cooling
- Indoor unit leaking or dripping water
- Ice forming on the indoor unit or its pipework
- Outdoor unit not starting or cutting out
- Tripping breakers and electrical faults
- Fault codes, flashing lights and unresponsive remotes
- Rattling, buzzing and grinding noises
- F-Gas leak detection and repair
Worth knowing first
A little of this might mean you do not need to call us at all — we would still rather you knew it.
Check the basics before booking a callout
Is the unit actually receiving power, and is the remote set to cool rather than fan, dry or heat? Is the outdoor unit clear of anything blocking the airflow around it? If the remote seems dead, many wall units have a small button under the front cover that starts them without it. If that works, the remote is the problem, not the system. These checks sound obvious and still explain a fair number of "it has stopped working" calls.
Water indoors is usually drainage, not a leak
When an indoor unit is dripping, the refrigerant is rarely to blame. The unit pulls moisture out of the air as it cools, and that water has to drain away. Usually the drip is a drain pipe blocked with dust and slime, a small condensate pump that has stopped, or a pipe that runs too flat. The fix is straightforward, but ignored for long enough it will mark a ceiling just as badly as any plumbing leak.
Ice on the unit means switch it off
Frost or ice on the indoor unit, or on the pipes outside, usually means too little air is passing over the cooling coil or too little refrigerant is in the system — a blocked filter, a slow leak or a struggling fan. Switch it off and let it thaw on its own; chipping at the ice damages the thin fins behind it. Frost on the outdoor unit while the system is heating in winter is different: that is normal, and the unit clears it itself.
Note the code before you reset anything
Most modern units show a fault as a code on the display or a pattern of blinking lights. Codes differ from make to make, so note the model as well. Then switch the unit off at its isolator switch for a few minutes and try again. If the same code comes straight back, leave it off and tell us what it says when you ring.
A unit that trips the breaker should not be reset repeatedly
An electrical fault that keeps tripping the circuit is not solved by resetting it and hoping. Repeated tripping usually means a fault getting worse, and continuing to run it can turn a repair into a replacement.
A new noise is worth a call
A rattle is often something simple: a loose panel, a bracket that has worked free, or leaves caught in the outdoor fan. A scraping or whining that follows the fan can be a motor bearing starting to go. Clunks or grinding from the outdoor unit as it starts up are more serious. A fan motor replaced early is a smaller job than one left running until it seizes.
A system that needs regassing has a leak
Air conditioning is a sealed system. It does not use refrigerant up, so if the charge is low, some has escaped. Topping it up without finding the leak means paying for gas that will leak out again, releasing a potent greenhouse gas as it goes. The rules expect leaks to be repaired, not just refilled, and that work is legally restricted to F-Gas registered engineers — not a job for a general handyman, whatever they charge.
When a repair stops being worth it
Most faults on a reasonably modern system are worth fixing. The sums change with a failed compressor on an older unit, where the repair can come close to the cost of a new system, and with anything still running on R22 — an older refrigerant that can no longer legally be used to recharge a system. Either way, you get both prices and the decision stays with you. Our air conditioning replacement page covers that choice in more detail.
Common questions
Why has my air conditioning stopped cooling?
Commonly a refrigerant leak, a fault with the outdoor unit, or in some cases just a filter so clogged it restricts airflow. A faulty temperature sensor can also make a unit ease off before the room is cool. We check the straightforward causes first before assuming the worst.
Why is my indoor unit leaking water?
Nearly always the condensate drain — either blocked or not falling correctly — rather than anything to do with the refrigerant. Once we can actually see the drain run, it is usually a quick job to put right.
The outdoor unit is running but the room is not getting cooler. Why?
The outdoor fan can keep turning while the compressor, the part that does the actual cooling, fails to start. Low refrigerant or a badly blocked filter can look much the same. Tell us whether the outdoor fan is spinning and whether a code is showing.
Can you repair a system you did not install?
Yes. Parts for older or less common makes can take longer to track down, and if that applies to yours we will say so when we price the repair.
Is a refrigerant leak expensive to fix?
It depends on where the leak is and how accessible the pipework is. We find and confirm the leak first, then quote for the repair — never the other way round.
Should I keep using it until the engineer arrives?
Not if it is leaking, icing up, tripping the electrics or making a new grinding noise — running it with a fault like that tends to make the repair bigger. If it is simply cooling less well than it used to, it is usually fine to use until the visit.
More air conditioning work we take on
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Air Conditioning Maintenance
Annual maintenance that keeps a system cooling efficiently and catches a refrigerant leak before it becomes a breakdown.
More on Air Conditioning Maintenance -
Air Conditioning Installation
Split and multi-split air conditioning, sized and sited properly, fitted by F-Gas registered engineers.
More on Air Conditioning Installation -
Air Conditioning Replacement
Swapping out a system that is worn out or failing — including older units on a refrigerant that can no longer be topped up.
More on Air Conditioning Replacement
Need air conditioning repair in London?
Describe the problem and give us your area, and we’ll tell you the price before anyone starts work.