What is VRV?

A VRV® represents Daikin’s ultimate technology in climate comfort and energy efficiency for small to large-sized offices, hotels or other commercial facilities, providing year round heating and cooling. Daikin invented the revolutionary VRV® (Variable Refrigerant Volume) technology in 1982. Now, Daikin has taken its flagship product to new heights, with innovations such as water-cooled VRV®WIII, Heat Recovery systems, systems for cold climates (VRV® III-C).The result? Enhanced comfort and energy-savings compared to previous VRV® generations.

What is IManager

Intelligent Manager – is a full control and management of VRV systems (maximum 200 groups).

Daikin’s computerised control systems not only provide the highly sophisticated regulation and day to day monitoring necessary for modern, hi tech air conditioning installations – they also provide owners, landlords and tenants of commercial buildings with valuable performance data on consumption as well as wide range of operating parameters. Dedicated central control can be applied to both VRV and mixed VRV/Sky Air and Split installations with up to 1,024 indoor units and can also be integrated with building management systems.

What is a heat pump?

A heat pump is a refrigerant based system (like your refrigerator at home but in reverse). The system can absorb low grade heat from the air (air source), water (water source) or ground (ground source), and raise its temperature efficiently to be suitable for space heating and/or hot water.

A heat pump absorbs free energy (heat) from a low-temperature source (air, water or ground) and upgrades it to a higher temperature, via the refrigerant cycle. Heat pump efficiencies range from 3:1 to 5:1 (300-500%) i.e for each 1kW of electricity consumed between 3kW – 5kW of heat energy can be absorbed and transferred. By contrast, conventional fossil fuel boilers produce less heat output, about 0.85kW for every kW consumed, therefore heat pumps are more cost effective, eco-friendly and use renewable energy for the greater good of our environment.

The heat pump is based on refrigerant cycle (like your fridge at home but in reverse) and basically comprises of 4 essential components.

The Evaporator — absorbs heat from renewable source (air, water, ground)
The Compressor — raises pressure hence temperatures of absorbed heat
The Condenser — rejects upgraded heat to the source inside (air or water)
The Expansion Device — reduces pressure/temperature to allow evaporation (heat absorption) at low temperatures.
The refrigeration cycle is used also in supermarkets, Air conditioning system, Cold store, Car air-conditioning (Climate control), Central air-conditioning systems etc.

It can provide water temperature up to 55°C (without backup electric heater) in ambient temperatures as low as -15°C with very high seasonal efficiency of up to 450%.

What is meant by the terms COP and EER?

The terms COP (coefficient of performance) and EER (energy efficiency ratio) describe the heating and cooling efficiency of air conditioners. They indicate the ratio of heating or cooling provided by a unit relative to the amount of electrical input required to generate it. Thus, if an air conditioner generates 5kW of heat from a 1kW electrical input, its COP is said to be 5.0. Similarly, if an air conditioner generates 5kW of cooling from a 1kW electrical input its EER is also said to be 5.0. The higher the COP and EER, the more energy efficient is the equipment.

Can air conditioning make you ill?

Only an ill maintained air conditioning system can make you ill. A well maintained air conditioning system can only contribute to a healthier environment.


Because it controls humidity levels the growth of dust mites and molds is reduced. Air conditioning maintains humidity levels of 40 – 60% which is positive for persons with allergies.


Air conditoning may have integrated ventilation. Mechanical ventilation is getting more and more important because of the way houses are built these days. The supply of fresh air will prevent the sick building syndrome.


All units are equipped with a filter. Depending on the type of system and the needs of the customer, the type of filter will vary. The effecitiveness of a filter goes from catching dust and particles over fine dust and pollen, bacteria, virusses and odours and even microbes and smoke.

It is essential to replace the filters on a fixed period. When you replace the filters too late you risk that the oversaturated filters start distributing bateria instead of catching them.


When the equipment is correctly selected there will be no draught. This is the job of specialists and should be calculated by an installer. A system with too low capacity will not be able to reach the desired temperature. A system with too high capacity will lead to draught and fluctuating temperatures.

Cold draughts?

Cold draughts are sometimes associated with air conditioning and indeed, this can be caused by incorrectly conceived systems. The likely effect on personnel resulting from the location of the indoor unit and its air distribution pattern must therefore be considered at the design stage.

The height of the ceiling is also relevant. Air conditioning equipment manufacturers generally assume the optimum ceiling height for a direct expansion system to be between 2.70 and 3.50 metres. Cold air at about 16°C supplied from this height is able to mix with warmer room air before reaching personnel level, thereby obviating any feeling or draught.

Notwithstanding this, in applications not meeting this general standard, a quality air conditioning system can invariably be “tuned” to compensate.

Clearly, unit location as well as ceiling height and shape have a major influence on draught or the lack of it. Explaining this requires a few comments concerning the properties of cold air. Cold air has a tendency to “stick” to the ceiling for a period prior to descending. This is known as the “Coandă effect” and it helps the cold air and surrounding air to mix before dropping down into the room.

Unfortunately, the existance of any barrier such as a ceiling beam, has a detrimental effect on this by interrupting the air flow. In such a case, cold air colliding with the beam will sink immediately, to the certain discomfort of any individual unlucky enough to be seated directely below.

Similarly, two units located opposite to each other will generate cold air flow collision in much the same manner.

The refrigerant cycle: what is it?

n air conditioner works similar to a refrigerator. The refrigerant flows through the system, and changes in state or condition. There are four processes in the ‘refrigeration cycle’.


The compressor which pumps the refrigerant around the system, is the heart of the air conditioner. Before the compressor, the refrigerant is a gas at low pressure. Because of the compressor, the gas becomes high pressure, gets heated and flows towards the condenser.
At the condenser, the high temperature, high pressure gas releases its heat to the outdoor air and becomes subcooled high pressure liquid.
The high pressure liquid goes through the expansion valve, which reduces the pressure, and thus temperature goes below the temperature of the refrigerated space. This results in cold, low pressure refrigerant liquid.
The low pressure refrigerant flows to the evaporator where it absorbs heat from the indoor air throught evaporation and becomes low pressure gas. The gas flows back to the compressor where the cycle starts all over again.
In case of a heat pump the cycle can be reversed.

What about legionella?

The legionella bacteria is a natural inhabitant of water. Temperature is of great importance for the legionella proliferation. Especially temperatures between 40 and 50°C may lead to colonization of the bacteria.

Daikin e.g. does not use water in its air conditioning systems. So no harm for humans can be caused. In chilled water systems for industrial purpose, the legionella bacteria can not live because of the low temperature of the water in the closed circuit.

What are the influences on the capacity need?

Throughout the ages, we have sought to improve the level of comfort offered by our surroundings. In colder regions, we have tried to heat our dwellings and in warmer climates, to cool them down because if we are not comfortable, we can neither work nor relax. But thermal comfort vital to our well being, is subject to three basic influences:

The Human Factor

Our clothing and activity level and how long we remain in the same situation.

Our Space

Radiation temperature and surrounding temperature.

The Air

Its temperature, velocity and humidity.

Among these influences, the human factor is somewhat unpredictable.

The others can be controlled in order to provide that much sought after feeling of well being.

Changing patterns in construction, working practises and internal occupancy levels have created.

New parameters within which designers must operate.

Modern buildings for instance, generate far more heat than their predecessors of say, 50 years ago and there are several reasons for this:

Solar Infiltration

Developments in building technology have also given rise to an increased use of glass – even when solar protective glazing is fitted, solar gains can be considerable.


Increasing numbers of occupants, each generating some 120W/h of heat, are routinely stuffed into office areas.

Electrical Appliances

Computers, printers and photo copiers, all part of the modern offices scenario, also generate substantial heat loads.


Many modern shops could be adequately heated by their lighting alone heat gains in the order of 15-25W/m² are not uncommon in Europe.


Introducing the outside air into a building also introduces its temperature something of a problem if it’s 30ºC outside!

What is heat transfer?

Heat always flows from a warmer substance to a cooler one. In reality, the faster moving molecules transfer some of their energy to slower ones. Thus the faster molecules slow down a little and the slower ones speed up. Expressed simply, this means that when it is hot outside, the heat attemps to ‘invade’ colder interior spaces.

Heat can be transferred from one body to another by any of the following methods:

By a wave in motion (similar to light waves) in which energy is transmitted from one body to another without the need for intervening matter.
By the flow of heat between parts of a substance or from one substance ot another in direct contact.
By transfer via a fluid or air.

What is inverter technology?

The inverter technology is integrated in the outdoor unit. The inverter technology can be compared to the technology in a car: ” The harder you push your accelerator, the faster you go.”

An inverter unit will gradually increase its capacity based on the capacity needed in the room to cool down or heat up the room. The non-inverter can be compared with switching on or off a lamp. Switching on this type of unit will start to run on full load.

Advantages of the inverter technology:

You reach much faster the comfort temperature you want
The start-up time is reduced by 1/3
You save a lot of energy and also money: 30% less power consumption
Avoids cycling of the compressor meaning that there are no voltage peaks
The energy consumption cost is reduced by 1/3 (compared to normal on/off units)
No temperature fluctuations

What is sound pressure/sound power?

Sound pressure level (Lp)

Is a measure of the sound energy emitted from a source of noise, expresses in decibel or dBA.

Sound power level (Lw)

Is the above but measured in predefined conditions.

The sound power level is independant on:

The location of the equipment
The environmental conditions, and
The distance from the measurement point
The sound power level can be considered as the more precise of the two. The sound power will have a higher value than the sound pressure, don’t be mislead by this.

What is the difference between sensible and latent heat?

Two forms of heat are relevant in air conditioning:

Sensible heat
Latent heat
Sensible heat

When an object is heated, its temperature rises as heat is added. The increase in heat is called sensible heat. Similarly, when heat is removed from an object and its temperature falls, the heat removed is also called sensible heat. Heat that causes a change in temperature in an object is called sensible heat.

Latent heat

All pure substances in nature are able to change their state. Solids can become liquids (ice to water) and liquids can become gases (water to vapor) but changes such as these require the addition or removal of heat. The heat that causes these changes is called latent heat.

Latent heat however, does not affect the temperature of a substance – for example, water remains at 100°C while boiling. The heat added to keep the water boiling is latent heat. Heat that causes a change of state with no change in temperature is called latent heat.

Appreciating this difference is fundamental to understanding why refrigerant is used in cooling systems. It also explains why the terms ‘total capacity’ (sensible & latent heat) and ‘sensible capacity’ are used to define a unit’s cooling capacity. During the cooling cycling, condensation forms within the unit due to the removal of latent heat from the air. Sensible capacity is the capacity required to lower the temperature and latent capacity is the capacity to remove the moisture from the air.

What are allergens?

Allergens are impurities in the air that can bring on an allergic reaction. In an urban environment, a mixture of these allergens with other impurities present in the air – called adjuvant substances – such as Diesel Exhaust Particles (DEP’s) produced by engines and Volatile Organic Compounds (VOC’s) present in building materials, cosmetics, etc. can turn allergens into heavy allergens. These in turn can have increased negative health effects such as aggravated symptoms and the triggering of latent allergies.

What is catechin?

Catechin is a natural anti-bacterial substance derived from tea leaves that kills germs that can attach to these particles. The filtering surface of a pleated filter is approximately 1.5 times larger than that of a conventional flat filter.

What is air purification?

This is where an anti-fungus filter is used that catches allergy-causing mites, smoke particles and odours, ensuring the air in your environment is cleaner and fresher.

Why we should be concerned about 'drop-ins'?

Not in any order of priority:

Equipment manufacturers do not/will not recommend the use of any refrigerant other then that which it was optimised to use. No warranty will apply to any major replacement components where alternative refrigerants have been applied and spare parts for R-22 kit are becoming increasingly difficult to obtain anyway!
Retro fill solutions are almost certain to reduce the operating efficiency of the equipment with resulting increased electricity consumption higher running costs and indirect Global Warming impact.
Retro fill solutions will do nothing to reduce the leakage potential of equipment designed to operate with HCFC R-22.
Any encouragement of a conversion option is encouraging the continued use of older equipment that statistically is more likely to leak then new equipment. The F Gas Regulation seeks to improve containment so the last thing we need is to endorse actions that could increase leakage potential.
All these so-called Alternative refrigerants are blends of HFC gases each element of which at a different pressure — even the smallest leak will change the constituent ratios of the blend. This means the characteristics of remaining gas changes and this will further detract from the performance and reliability of the equipment. You can’t ‘top it up’ either because the blend becomes something else again. The only option is to evacuate dispose of the old gas and start again — very expensive and the equipment may already have suffered the consequences.
Any encouragement of a conversion option is encouraging an avoidable increase in the use of HFC refrigerants and therefor increased GWP due to the fact that R-22 “alternatives” Will be required in at least the same volume as the original HCFC charge — whereas the majority of new HFC equipment require for lower volumes of refrigerant.
Any encouragement of a conversion option is encouraging the continued use of relatively inefficient equipment.
The use of retro fill alternatives particularly where flushing agents are necessitated have been found to further increase the leak potential of the converted equipment due to the need to create new openings to ensure the complete evacuation the agent.

Why the need for a yearly Maintenance Service?

It is recommended to have your system serviced each year as a preventative measure. By properly maintaining your system this will help save money on your energy bills by helping maintain the systems optimum efficiency and performance. A properly maintained system may also last longer which is important due to the expense of replacement. During your yearly maintenance, parts that may cause trouble when dirty can be cleaned to keep the system running efficiently.

What is VRV or VRF?

VRV is a system developed and designed by Daikin Industries that stands for “Variable Refrigerant Volume”. Daikin protected the term VRV so other manufacturers use VRF “Variable Refrigerant Flow”. In principle they both work the same and work extremely efficiently, are reliable, and an ideal energy saving solution for heating and cooling all types of buildings with minimum installation time or disruption.

The volume or flow rate of refrigerant within the VRV or VRF system is accurately matched to required heating or cooling loads thereby saving energy whilst providing more accurate control.

What is Energy Labeling?

Energy labeling allows consumers to easily compare and rate the efficiency of different types of electrical equipment including air conditioning systems.

Annual Investment Allowance (AIA)

AIA (Annual Investment Allowance) is designed for businesses investing in most plant or machinery, enabling them to claim full tax relief on up to £250,000 of the equipment expenditure in the tax year it is incurred.

The AIA is in effect an Enhanced Capital Allowance that works in the same way as the Energy Technologies List (ETL) however the equipment is NOT required to be on the ETL to quality for the AIA.

Who the AIA is available to?

Any individual carrying on a qualifying activity (this includes trades, professions, vocations, ordinary property businesses and individuals having an emplyment or office)
Any partnership consisting only of individuals
Any company (subject to certain limitations)
Benefits of AIA

Helping your customers gain a useful tax break on their investment
Making your customers aware can help to accelerate their decision making process
Who the AIA is available to?
Any individual carrying on a qualifying activity (this includes trades, professions, vocations, ordinary property businesses and individuals having an employment or office)
Any partnership consisting only of individuals
Any company (subject to certain limitations)
How to claim AIA?

To claim for AIA is as simple as ticking the Enhanced Capital Allowance box on a tax return form and including details of the plant or machinery that was invested in.

Further Information

If you would like further information please visit the view the HM Treasury document.


Unit operation questions

After the power switch is turned on, the air outlet flaps operate.

When the unit is turned on, the microcomputer operates the flaps to determine their position for initialisation.

In the microcomputer-controlled dry mode, the indoor unit fan operates at L for one minute when the outdoor unit (compressor) is not operating.

The monitoring function forcibly operates the indoor unit fan for one minute.

The air conditioner does not blow air immediately after it starts operation in the heating mode.

The air conditioner conducts a “warm-up” operation first so that it won’t blow cold air in the heating mode. The fan starts operating after one to four minutes of warm-up operation.

(The warm-up operation becomes longer when the outside air temperature is low. )

The air conditioner produces a water flowing sound.

The water flowing sound is produced by the refrigerant that flows inside the air conditioner.

This sound is more prone to generation when the defrost operation is activated in a heating operation.

The air conditioner produces an air releasing sound.

The air releasing sound is caused by a change of the refrigerant flow direction. This sound is generated when the air conditioner stops operating or the defrosting operation is activated in a heating operation.

The air conditioner stops operation (Operation lamp remains lit).

When power supply voltage fluctuates largely, the air conditioner may stop operating to protect the equipment. (When power supply returns to a normal condition, the air conditioner resumes operation after three minutes.)

The air conditioning produces a crackling sound.

Plastic parts such as the front panel produces a crackling sound when they expand or contract slightly due to temperature change.

The air flow suddenly becomes stronger during a heating operation.

When the air flow is set to LOW, the amount of air flow increases when the overload control is activated. (“Overload” is a condition in which the air conditioner operates under excess load. Overload can be caused by dirty filters.)

The air outlet flaps do not operate at the same time in the master and slave indoor units of a simultaneous operation multi-unit.

There is a slight time lag in the signal transmission between the master and slave units. It does not denote a malfunction.

The air outlet flaps sometimes operate during a cooling operation.

The air outlet flaps move when the frost prevention or ceiling soiling prevention function is activated.

The drain pump continues operating after a cooling operation stops.

After the air conditioner stops operating, the drain pump operates for several minutes in order to discharge condensate from the drain pan (condensate receiving tray).

The indoor unit fan operates after a heating operation stops (in an air conditioner equipped with a heater).

In order to reduce the temperature of the heater, the fan operates 60 to 100 seconds after the air conditioner stops operating.

The outdoor unit discharges water or steam.

The defrost operation activated in the heating mode removes frost, which turns into water or steam. A small amount of water is also discharged during a heating operation.

When the air outlet swing function is set to ON, the flaps remain at a horizontal position.

The flaps remain at the same position when room temperature reaches the set level and the thermostat turns off. When the thermostat is off, the flaps do not swing.


First Aid

The air conditioner does not cool or warm the room.

Check the following:

Make sure the air filters are not dirty.
Make sure the air inlets and outlets of the indoor and outdoor units are not blocked by objects.
Make sure the temperature setting on the remote controller is appropriate.
Make sure the doors and windows are closed.
Make sure the air flow and direction settings are appropriate.
Make sure ventilation fans in the room are not operating.

The air conditioner does not operate (Operation lamp is not lit).

Check the following:

Make sure the circuit breaker is not turned off and the fuse is not blown.
Make sure the power cord plug is connected securely to the service outlet.
Make sure there is no power outage.
Make sure the remote controller has new batteries.
Make sure the timer is not programmed mistakenly.

The air conditioner operates abnormally.

Lightning and radiowaves can sometimes cause abnormal operations of air conditioners.

Cut off the power supply by unplugging the power cord or turning off the circuit breaker, then re-supply power and restart the air conditioner.

The air conditioner stops in the middle of operation (ON timer in operation).

When the ON timer is set, the air conditioner may start as early as one hour before the set time in order to bring the room temperature close to the temperature set with the remote controller.

If the remote controller is operated (except ON/OFF operation) during this time period, the air conditioner enters the stop mode.

When this happens, turn on the air conditioner using the remote controller, and set the timer again.

The air conditioner stops operating (Operation lamp blinks).

Check to see if the air filters are clean.

Also make sure the air inlets and outlets of the indoor and outdoor units are not blocked.

The amount of drained water is large (as compared to the amount discharged in the previous year or the day before).

he amount of drained water varies depending on room temperature and humidity. A large amount of drained water does not denote a malfunction.

The indoor unit produces a mist.

The cold air blow out during a cooling operation reduces the temperature of the room air and sometimes generates a mist.

The remote control thermostat cannot be set.

When a multiple number of units are controlled by a single remote controller (group control), the remote control thermostat cannot be set.

When the operation mode is changed, the air outlet flap position also changes.

The flap control varies the flap position depending on the operation mode such as cooling and heating

How often should I have my equipment serviced?

Air Conditioning and equipment should be serviced at least once a year.

Why should I have the equipment serviced?

Annual servicing should include cleaning the system, checking for problems or potential problems and making adjustments to enhance efficiency. The benefits include:

Increased longevity of the system.
Discover and fix any potential problems.
Provide optimal efficiency to help lower energy bills.
May help towards a healthier more environmentally friendly environment.
Can help drastically reduce the chance of a system break-down.

My system has a warranty - Why do I need a maintenance contract?

All air conditioning systems need regular maintenance to ensure safety levels and optimum operational efficiency. A warranty is only applicable if the equipment or system has regular maintenance by an approved company or installer.