HVAC Resource Centre

The critical thing in relation to working on air conditioning systems is the safe handling of refrigerants – this is covered by F-gas legislation and only trained and accredited engineers are licensed to handle refrigerant. 

The other critical part of an air conditioning system is the power supply -  any alterations involving the power supply must always be carried out by a qualified electrician. 

The main factor governing the servicing of Air Conditioning systems is the mandatory annual check for any leaking refrigerant.  The refrigerant in your air conditioning system can be harmful to the environment if it leaks, as well as a potential health hazard.  For this reason, Fgas regulations stipulate that an annual check is required as a minimum. 

The actual servicing and cleaning of your units isn't required by any law or legislation, but is completely advisable, for a number of reasons:

• Keeping your system clean and healthy for the building occupants
• Ensuring optimum running efficiency of your system by keeping it clean
• Maximising the life of your system, by reducing strain on the key wearing parts
• Identifying any potential problems early, and before they escalate into worse problems

Every Air Conditioning unit will have built-in filters – these need to be cleaned on a regular basis by an Air Conditioning engineer, to prevent the build-up of dirt and debris.  Dirty or clogged filters will not only result in particulate matter in the air but also will put strain on your air conditioning unit and cause it to work less efficiently.

• Filtration within Ventilation systems vary massively, depending on the type of installation.  Very simply, the typical ventilation systems you see in the UK can be broken between
  • Packaged Mechanical Ventilation / Heat Recovery Units – these are smaller units, normally mounted above a suspended ceiling in the same way as an air conditioning units.  These will tend to serve one space or area, rather than a whole building.  In most cases, these units will have filters that are cleaned regularly.
  • Air Handling Units – these are larger ventilation units, often serving a whole building or a larger area.  They take up a lot of space and are therefore often situated on the roof, or in a plant room.  These units will typically have more complex filtration, with normally two sets of disposable filters installed – these should be changed on a regular basis to provide the best air quality and maintain the operation of the unit efficiency. 

There is a huge variation of filters available, but typically speaking there are two types of filters

• Pre-Filters  – coarser grade filter, normally a panel filter with a cardboard frame.  These should be replaced at least every 6 months
• Main Filter – fine grade filter, normally a ‘bag’ filter with a metal frame.  These should be replaced at least every 12 months

If you notice any build-up of ice on the pipework or the coils, then call us immediately.  Normally an ice build-up indicates either a very dirty unit or a refrigerant leak, both of which need addressing urgently to preserve the unit.  Left unattended, the unit could eventually fail, giving rise to an expensive repair or replacement of the whole unit. 

Over time you may notice a general drop in cooling or heating performance, which could be for a number of reasons.  If the unit has not been serviced for a while (6 months or more) then we would recommend that as the first action.  This will also help to pick up any other issues that could be present including a possible refrigerant leak. 

In particular, units installed in locations such as food production plants, or where the condenser is situated near a busy street, units can get clogged up with dirt and dust, requiring much more regular servicing.

If an Air Conditioning unit isn’t regularly serviced, it can quickly clog up with dirt and dust, which in turn forces all of the working parts to work harder.  Not only does this increase the wear on parts and reduce their lifetime, but it could well impact your electricity bill with increased costs.  By carrying out regular servicing of your Air Conditioning, you can ensure efficient operation and maximum life of your units.

Regular servicing normally fixes issues relating to the smells given off by Air Conditioning units.  Smells develop due to the condensate produced in the cooling process and the continual heating and cooling in this damp environment.  This can cause mould to grow in and around the coil, so regular cleaning is essential to prevent this build-up.

Sometimes we get reports of poor airflow from Air Conditioning units, which could be for a number of reasons.  The first thing to check is whether the fan speed has been turned down on the controller.  Next, check for an excessive build-up of dirt, which will slow down the working of the unit.  It could also be that the fan motor has developed a fault and needs replacing, normally you can tell if this is the case from the noise given off by the motor during operation.

R22 is a hydrochlorofluorocarbon (HCFC) refrigerant that was traditionally commonly used in Air Conditioning systems. The main threat of this type of refrigerant is its effect on the ozone layer if it leaks.  Modern refrigerants are not only safer but are also more efficient and ever-improving in their performance. 

Yes, you can continue to use it, providing it remains operational and is regularly serviced.  As soon as an R22 system develops a leak, or the system breaks down, it should be replaced with a modern equivalent.  While the original phase-out date set by the government has passed without actual implication for people who still have R22 systems, it is likely that legislation in the future will require building users to switch out systems containing R22 refrigerant. 

Systems that still use R22 refrigerant are not illegal as long as they keep running.  R22 was banned from being used in new equipment in 2004 and there was a phase-out plan put in place to replace R22 with newer and safer refrigerants. Once an R22 system fails, it can only be replaced with a modern equivalent.

https://www.gov.uk/government/collections/fluorinated-gas-f-gas-guidance-for-users-producers-and-traders

In short, yes.  Refrigerant leaks can be harmful to the environment and to human health.  This is why you are required by law to have your Air conditioning system checked by an F-gas accredited engineer at least once a year.

Minor leaks of refrigerant will be picked up on a routine service, and can then be investigated further by a qualified engineer – this points up again the importance of routine servicing.

A significant or sudden refrigerant leak will result in a sudden drop in performance of your air conditioning system – this will need investigating by a qualified air conditioning engineer, to perform a leak test and repair.

One of the most common reported issues we get is in relation to water leaks from Air Conditioning units.  In most cases, these are caused by blocked or failed condensate pumps, or sometimes by a kinked condensate hose or pipe.  This is normally a straightforward repair and can be carried out without too much intrusion or cost. 

This can vary depending on a few factors, but as a general guide, we refer to three things – Checked, Cleaned, and Compliant. 

• Checked - Equipment has been thoroughly checked, including system operation, electrical connections and components e.g. pumps, fan motors, valves, insulation, condensate drains, and much more
• Cleaned - Systems have been thoroughly cleaned internally and externally, including indoor and outdoor units, coils, and filters. Our service ensures systems meet the government recommendation, which has been reinforced in the pandemic.
• Compliant - Your F-Gas log is now updated with this service information and can be accessed via our online resource centre (www.salixmechanical.com), to ensure that you are compliant with legal requirements.
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There are a number of factors that will affect your service frequency and therefore there is no ‘one-size’ approach to this.  Probably the most common is 6-monthly servicing, but the factors that affect this include:

• Type of Equipment Installed – for example, a small domestic unit won’t need the attention that a multi-floor commercial VRV system would.
• Location of Equipment installed – units installed in dusty environments, food production plants, near to busy roads etc. will all require more maintenance
• The usage of the equipment – are the units occasionally used for comfort cooling, or are they on 24hrs a day to cool critical production facilities?
• The importance of the equipment – related to the last question, but an Air Conditioning unit that is keeping a critical IT suite cooled will need more preventative maintenance 
• Any manufacturer-specific guidelines or conditions – sometimes the manufacturer will state the minimum service intervals if the equipment warranty is to be upheld
• The age of the equipment – typically speaking, the older the equipment, the more likelihood of breakdowns and therefore the more advantageous regular servicing would be.  However, this doesn’t in any way mean that new equipment doesn’t need servicing. 
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The answer to this question depends on a few factors.  Our answer to this question is that every workplace has its own unique parameters and the ventilation needs will vary accordingly.  Factors include opening windows, natural ventilation sources, use of the workspace, and the density of people in the space.

There is a provision within UK building control for commercial buildings of a certain size with opening windows, not to require the installation of mechanical ventilation.  However, in practice, the windows often remain closed in these buildings, and the air quality can drop to an alarming level, especially in extreme weather.  In the summer the windows are kept closed to allow the air conditioning to cool down the space and in the winter the windows are kept closed to keep the wartth in – in both cases, there is no fresh air ventilation to the space, causing air quality to drop. 

Ventilation is often confused with air conditioning.  Ventilation is the actual cycle of stale air being replaced by fresh air from outside the building, as opposed to air conditioning which simply cools and/or heats the air within a building.  There is a common misconception that the air that is blown out of an air conditioning system is fresh air from outside – this isn’t the case, it is simply recirculated, cooled air.  In the case of a typical ceiling-mounted air conditioning unit, air is usually drawn up through the centre, cooled, and then blown out of the side-facing louvres.