Air Conditioning Repair in London

Air conditioner repair for homes and businesses

When an air conditioner stops cooling, blows warm air, trips the electrics, leaks water or shows a fault code, it needs diagnosis rather than guesswork. We arrange repairs for wall-mounted splits, multi-split systems, ceiling cassettes, ducted units and commercial systems in offices, shops, restaurants and server rooms.

Home systems usually fail through a single component: a capacitor, fan motor, sensor or control board. Commercial systems run longer hours, so wear on compressors, contactors and condensate pumps is more common. Either way, the engineer finds the cause before replacing anything.

Common air conditioning faults we repair

Not cooling or blowing warm air: the most common callout. Causes range from low refrigerant and dirty coils to a failed capacitor or compressor, so the engineer tests each in turn before replacing anything.

Compressor noise and failure: the outdoor unit hums, clicks or buzzes but does not cool. The cause may be a failed start capacitor, a contactor or an overheated compressor; the engineer tests each before condemning the compressor, which is the most expensive part.

Refrigerant leaks and frozen coils: weak cooling with ice on the pipes or indoor coil usually means low refrigerant from a leak, or restricted airflow. The leak is found and fixed before any regas. Faulty controllers: dead wall controllers, unresponsive remotes and incorrect sensor readings make the unit short-cycle or ignore its setpoint. Electrical faults: tripping breakers, dead PCBs, damaged wiring and failed fuses need safe isolation and testing. Water leaks: blocked condensate drains or failed pumps cause drips from the indoor unit.

Our diagnostic process

Tell us the make, model, symptoms and any fault code when you call. Photographs of the unit labels help the engineer bring likely parts. On site, the engineer checks power supply and controls, reads fault history, measures operating pressures and temperatures, and tests motors, capacitors and sensors.

You then receive a clear explanation of the fault and a written price for the repair. Work only goes ahead once you agree. If a repair would cost more than the system is worth, the engineer will say so and we can quote for replacement instead.

Same-day and 24/7 emergency air conditioning repair

If you are searching for air conditioning repair near me because a unit has failed, call and say it is an emergency. Phone lines are answered around the clock, and we arrange the earliest suitable local engineer for same-day attendance where availability allows. For offices, shops, restaurants and server rooms that cannot trade without cooling, emergency air conditioning repair is prioritised. Attendance depends on your postcode, the equipment and engineer availability, and we confirm the expected time on the call rather than promising a fixed window.

F-Gas certified repair engineers

Any repair that opens the refrigerant circuit must be carried out by an F-Gas certified engineer under the Fluorinated Greenhouse Gases Regulations 2014. Air conditioning commonly uses R32, R410A or R407C, and these refrigerants are not interchangeable. The data plate decides which gas and charge weight are correct. This page covers building air conditioning, not car air conditioning.

Air conditioning leak repair

A refrigerant leak shows as weak cooling, ice on pipes or a coil, oily marks at joints or low-pressure fault codes. Adding gas without fixing the leak only delays the next failure, so leak repair comes first.

Leak detection

The engineer checks flare joints, brazed connections, service valves and coils using electronic detection and bubble testing to pinpoint the leak.

Pressure testing

After the repair, the circuit is pressure tested with oxygen-free nitrogen and then evacuated to remove air and moisture, confirming it is sealed before any refrigerant goes back in.

Regas after the repair

Once the circuit holds pressure, a weighed charge restores the correct refrigerant level. For the recharge itself, see our air con regas service from £120 plus VAT or the air con refill guide.

Air conditioning repair prices

These are typical costs already published on our site. Your final price is fixed in writing after diagnosis. For new system prices, see our air conditioning cost guide.

Repairs for all major brands

Our engineers work on Daikin, Mitsubishi Electric, Toshiba, Fujitsu, Samsung and LG systems, among others. If repair is not worthwhile, our main air conditioning installation service covers replacement units with fitting.

Portable air conditioner repair: common faults

Portable air conditioning repair starts by separating an equipment fault from a problem with the room or exhaust arrangement. A unit can run continuously yet struggle to cool when its hot exhaust returns through an open window, the hose has become detached, or the room gains more heat than the unit can remove. Check the operating mode, temperature setting and accessible filter using the manufacturer's instructions before booking a diagnosis. A full water tank or drainage alarm can also interrupt cooling, depending on the model.

Exhaust hose and venting problems deserve particular attention. A crushed hose, blocked outlet or unsuitable extension can restrict airflow and cause overheating. Keep to the manufacturer's permitted hose arrangement and use a suitable window seal; do not assume that a longer hose will work. For filter cleaning and routine condition checks, see our air con servicing page. Switch the unit off if it repeatedly trips the electrics, smells burnt or has damaged wiring.

A failed fan motor can leave either the room-air side or the heat-rejection side without adequate airflow. Control board faults, damaged sensors and failed controls can prevent the compressor starting or make the unit stop unexpectedly. Compressor failure needs electrical and mechanical diagnosis: a hum or click alone does not prove that the compressor is beyond repair. Refrigerant leaks are a different issue from water leaking out of a condensate tank. Our air conditioning leak repair guidance explains why finding the leak comes before considering a recharge.

Which portable air conditioning units can be assessed?

Tell us whether your equipment is a single-hose portable unit, a dual-hose model, or a portable split with separate indoor and outdoor sections. We assess repair enquiries for domestic room coolers and larger portable units used in offices or temporary workspaces, but confirm model suitability and engineer availability before booking. A water-filled evaporative cooler is not a refrigerant air conditioner; its maintenance needs are different, so identifying the equipment correctly avoids an unsuitable visit.

The model label matters more than the appearance of the casing. Please have the manufacturer, model number, refrigerant marking, symptoms and any displayed fault code available when you call. Some portable air conditioners use R290, a flammable refrigerant, rather than the refrigerants commonly found in fixed split systems. Refrigerant-circuit work must follow the requirements for that refrigerant and equipment. Do not puncture pipes, attempt a DIY recharge or use a gas chosen for another model. Our air conditioning regas page describes diagnosis before recharge; it is not a promise that every portable unit can be regassed.

Repairability also depends on access to components and the supply of exact replacement parts. A compatible-looking board or motor is not necessarily safe or correct. For businesses relying on cooling each summer, our air conditioning maintenance contracts page covers planned aftercare; ask us whether your particular equipment can be included rather than assuming every portable model is covered.

Portable air conditioning repair or replacement?

Repair is often worth investigating when the problem is confined to a hose, drainage arrangement or an accessible replaceable component. Replacement becomes a stronger option when the compressor has failed, a coil is damaged, parts are unavailable, or several faults would need separate work. Compare the total written quotation with an appropriate replacement, not just the price of a spare part. Check any manufacturer warranty before authorising independent work, because the warranty may provide a different repair route.

There is no published portable-specific fixed repair price on this page. The existing general repair ranges above are guidance, not a guarantee that a small portable unit can be repaired for the same amount. We confirm the scope and price before work goes ahead. If repeated breakdowns or insufficient cooling make replacement more practical, consider room size, ventilation, noise and how often the equipment will run. Our air conditioning units page covers existing catalogue options, while the installation cost guide helps compare a fixed system where permanent installation is suitable. A fixed system is a separate purchase decision, not a necessary outcome of a portable repair enquiry.