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What Do Those Guys Do When They Service Your AC?

Well, I guess that depends on whether they are professionals or the ‘Jack of All Trades’ type that turn up all too frequently with only a hammer – no matter what the job is that you need!
Very few people understand what actually takes place as part of a proper service of an Air Conditioning (AC) system, as there isn’t much to see, apart from either the legs of a technician with his head in the ceiling or an empty ladder once they have disappeared onto the roof.

Colin Thomas, Business Partner at Jim Will Fix It Services, takes us through what actually should happen when the technician disappears out of site (and sometimes out of mind).


There is nothing more critical for a property in the UAE than effective air conditioning during the summer months. For many people however, this only becomes a priority two minutes after an AC unit stops cooling! Whilst sometimes unavoidable, there are lots of things that you can do to help avoid unnecessary breakdowns and also minimise your energy bills. Before we discuss the specifics, lets start with a look at the basics:

What Parts Does Your AC Have?

There are a few different types of AC system commonly used here in the UAE:

  • Split AC:  Most commonly used in villas or low-rise apartment buildings, this system is called ‘Split’ because it consists of both an Outdoor and Indoor component that work together to produce the required cooled air. Basically, the outdoor unit’s main job is to produce the cooling and the indoor unit is there to convert this cooling into cold air ready for it to be distributed to where it is needed.
  • Chilled Water (District Cooling): Chilled water systems tend to be found in high-rise apartment blocks here in the Middle East although some villa developments such as Green Community and Jumeirah Islands here in Dubai have also adopted district cooling AC systems. The main difference with these systems is that the cooling comes from a central provider for all properties and is distributed to each property via a pipe providing a constant flow of chilled water. Hence all that is needed is an indoor heat exchanger to convert the chilled water into cool air.
  • Package AC: Often used to chill large spaces within large low-rise building such as shopping malls or hotels, the principles of a package unit are very similar to a split AC system, except that all the required components are located in one ‘package’ on the roof of the building.


‘Servicing’ is the most abused word in the AC world, hence always remember to ask more questions when someone claims to be servicing your AC system! Regularly, we hear from our clients that “a little man came with a ladder, ‘serviced’ all the A/C’s in their villa and it only took 15 minutes in total.’’ THIS IS NOT AN AC SERVICE! The maximum that could be done in this time is to spray down the indoor air filters which is only a small part of what is required.

So What Is a Proper AC Service Then?

A comprehensive AC service should take between 1/2hr and 45 minutes for each unit serviced. To work out how many AC units you have, count the number of temperature controllers you have on the walls as each corresponds to one unit.
As the majority of AC’s here in Dubai are split units, we are going to focus on this type of unit as an example of what should be included within the service. As mentioned, these units have 2 parts, the outdoor unit which is normally located outside on the roof or walls of the building and the indoor unit which will be above a false ceiling often in the bathroom areas. Both of these parts require attention :


  • Condenser Filters: These are the main radiators for the AC system and their job is to expel the heat removed from the property. Here in Dubai, these filters can get caked in sand and hence need to be regularly cleaned. To complete this thoroughly, the technician should use a power-sprayer rather than just the pressure from a domestic tap to ensure these filters are fully cleaned.
  • Compressors: These are the main “engines” of the system responsible for circulating the coolant. The technician should check both their electrical and mechanical condition to warn off future failures.
  • Capacitors: These act as the starter motor for the compressor. If your AC fails suddenly, a failed capacitor is often the culprit.
  • Filter Dryers: The gas must be kept both clean and dry to be effective and the filter/dryer does this job. The technician should check that these are not blocked and operating correctly.
  • Gas Pressures: The correct gas pressure is critical to the effective cooling of your system and hence must be monitored closely. We also only use US or European-made gas as this is much more stable and consistent versus the gas made in the sub-continent. This avoids future compatibility issues.
  • Wiring: As all of the wiring and electrical components are exposed to the harsh elements, general checks of all the wiring should be included each time the units are serviced.

Inside the Villa

The indoor part of a split AC system is known as the Evaporator. It looks like a big metal box with pipes coming out of it and is normally located above a false ceiling. This has a number of elements that need to be serviced:

  • Evaporator Air Filters: These should be cleaned to maximise airflow through the unit and disinfected to ensure any bacteria present are killed off.
  • Fan Motors: Noisy fan motors can cause nightmares and in most cases, they are easy to fix. Hence as part of a thorough service not only should their correct operation be checked but if noisy, the technician should also realign the fan motor, check the fan blowers are not damaged and also tighten the mounts.
  • Evaporator Wastes: The number one cause of AC leakage is blocked evaporator wastes caused by dirt build up from the evaporator. Hence these should be checked and cleared if necessary.
  • Evaporator Trays: The tray is there to catch the water produced as a result of the air being cooled and hence tends to get gunky with dirt and grease carried in the air. As a bare minimum, these trays should be disinfected and ideally removed and power-washed.
  • In-room air vents: After even a couple of months, the air vents in each room can look unsightly and hence should be cleaned during every service. Most vents have removable filaments to make this easier and more thorough.
  • Temperature Check: This is the final check to make sure the whole system is working well. These days laser temperature gauges can read the temperature of the air coming out of the vents to 0.1 of a degree and for an average split AC, the reading should be between 15 – 17 degree’s.

Duct Cleaning:

Remember the scene in Mary Poppins with the chimney sweep. Well duct cleaning is simply a more modern version of chimney sweeping that uses a big mechanised rotating brush to clean the dirt from the duct and an industrial-sized vacuum cleaner to suck the dirt out of the vents.
This is a very different proposition to AC servicing and should primarily be considered if you have family members with respiratory problems or you live in an older villa. As most of the properties here in the UAE are only a few years old, this is not often necessary and will only assist to clean the dust and NOT to assist to improve the cooling.

Myths & Truths of AC

  • AC’s don’t need to be serviced if not used
    Wrong! Half of a split AC system is on the roof and exposed to the elements. Hence they will get dirty and therefore less effective whether you use them or not. However use, will obviously speed up the need to get an AC serviced. However most chilled water systems will be less affected in this way.
  • Two AC’s in my property are not cooling. Are their problems linked?
    Unlikely but possible if it is an electrical fault.
  • My AC doesn’t work. Doesn’t it just need more gas?
    Not always. Bizarrely, sometimes too much gas will stop the unit cooling and very often, the gas is just fine and the issue stopping an AC from cooling is something completely different.
  • If I regularly service my AC’s, will my energy bills be any lower?
    A clean AC is an efficient AC, as it is able to cool to its maximum potential and therefore the compressor does not need to run as much. Hence yes, your energy bills will be lower.
  • So, feeling like an AC guru and think you could do it yourself?
    Just remember that as the process described above involves mixing electricity with water, it is best left to the professionals like us! Feel free to call us at Jim Will Fix It on 800-FIX (800-349) or for more details.

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