|
Q)
|
What is comfort air conditioning??
|
|
A)
|
Often referred to as comfort cooling, this is the provision
of comfortable conditions for the users of occupied areas.
If the temperature exceeds a defined limit, then cooling is
provided. There is no specific control on humidity levels,
but the system has an innate ability to dehumidify as a by-product
of the cooling process. In many cases comfort air conditioning
also includes a heat pump function to provide warm air in
the winter.
|
| |
|
|
Q)
|
What is close control air conditioning?
|
|
A)
|
This is environmental control of an area where usually both
temperature and humidity are held within defined limits. For
example to protect sensitive equipment or to ensure commercial
processes can be continued without being affected by changes
in climatic conditions. Typically close control tolerances
are + and- 1 deg C on temperature and + and- 5% on relative
humidity. In addition, defined levels of air filtration will
often be specified.
|
| |
|
|
Q)
|
What is the difference between sensible and latent duty?
|
|
A)
|
"Sensible" duty is a measure of a machine's ability to reduce
temperature whilst "latent" duty is its ability to remove
moisture, i.e. dehumidify. The sum of the sensible and the
latent duties gives the "total" duty. Most air conditioning
literature states the "total" duty of a machine,
so it is wise to check that the system under consideration
is actually capable of the sensible or latent duty that is
required in any particular case.
|
| |
|
|
Q)
|
What is low ambient control?
|
|
A)
|
This is a control device which allows an air conditioning
system to provide indoor cooling when the external ambient
temperature is low, such as in winter. It is needed, for example,
when an area has a high year-round heat gain so causing the
air conditioning to run all year. Fitting a low ambient control
prevents the evaporator from freezing. The most common method
is to vary the speed of the condenser fan in order to maintain
the head pressure (or high-pressure side) of the refrigeration
system. Thus, low ambient control is often also known as head
pressure control.
|
| |
|
|
Q)
|
What is an "auto-changeover" facility?
|
|
A)
|
On a heat pump system, which can provide both heating and
cooling, auto-changeover is the facility to set the controller
so that automatically selects cooling or heating depending
on the temperature of the room. Thus, when a temperature is
selected in auto-mode, the machine heats and cools as required
to maintain that setting
|
| |
|
|
Q)
|
What is PLASMA filtration?
|
|
A)
|
PLASMA is an air filtration system fitted to many LG air
conditioners. It removes particles down to 0.01 micron, including
tobacco smoke and pollen, and also deodorises. PLASMA filters
are concealed within the unit and are washable. It should
not be confused with PLASMA coil protection,
which is another LG feature.
|
| |
|
|
Q)
|
What is Jet Cool?
|
|
A)
|
Jet Cool is a function available on many LG air conditioners
for quickly cooling a room. In Jet Cool mode, a strong stream
of cold air is blown at high speeds for 30 minutes until the
room temperature has been brought down to 18 degrees C.
|
| |
|
|
Q)
|
What is a Chaos swing louvre?
|
|
A)
|
Chaos "natural breeze" is feature of many LG wall
mounted air conditioners. By varying the angle and speed of
the moving air distribution louvres, air is evenly distributed
throughout the room in order to provide a comfortable air
flow.
|
| |
|
|
Q)
|
What are Gold Fin outdoor and Plasma indoor coils?
|
|
A)
|
Gold Fin is a special coating applied to the outdoor coils
of many LG air conditioners to extend the life of the coil
by protecting it against corrosive elements in the air.
Plasma treatment of the indoor coil is a special treatment
to prevent ageing of the surface of the fins, so extending
the life of the coil by combating the reduction in efficiency
when untreated coils age. It should not be confused with PLASMA
air filtration, which is another LG feature.
|
| |
|
|
Q)
|
What is an Inverter air conditioner?
|
|
A)
|
An Inverter air conditioner uses an inverter circuit to regulate
the rotational speed of the compressor to match the output
of the compressor to the cooling or heat pump load. This reduces
the number of times the compressor stops and starts as the
load varies, so improving economy and reducing noise levels
compared to non-inverter models.
Inverters also improve significantly the efficiency of the
air conditioning system, reducing energy consumption and enabling
the system to achieve high COP and EER ratings.
They are used on split systems, multis and VRF systems as
part of the inbuilt control system.
|
| |
|
|
Q)
|
What are the pipe sizes, maximum pipe runs and lifts,
fuse ratings and other electrical requirements for LG and
Hitachi split systems?
|
|
A)
|
These vary from model to model. These details, plus information
on fuse ratings, start and run currents, refrigerant charges
etc for our current range of split systems and multi-split
systems can can be found in our Air Conditioning price list.
Information can also be downloaded as an Acrobat Reader (.pdf)
file:
LG systems:
Hitachi systems:
If you do not have Acrobat Reader it is also available as
a free download.
Note: use the rotate function in the toolbar of Acrobat Reader
to view these pages horizontally.
|
| |
|
|
Q)
|
What equipment is available for domestic air conditioning?
|
|
A)
|
A number of options can be considered. The least costly solution
are mobile units, but these tend to be noisy and also require
an open window or similar arrangement for the hot air discharge.
However they are quick and easy to install, normally being
plugged straight into a 13A socket.
More permanent solutions include split systems, for example
high walls or floor/ceiling convertibles as offered by LG
and Toshiba. These are quiet and efficient, but consideration
must be given to the location of the outdoor unit and pipework
to avoid an unsightly installation or noise nuisance from
the outdoor unit. If several rooms are to be air conditioned
then an LG or Toshiba multi-split has the advantage requiring
only one outdoor unit to supply several indoor units.
Another possibility is to install window units as commonly
seen in the USA and the Far East.
Even if the home owner prefers to use conventional heating
in the winter, the heatpump option on many air conditioners
is useful as it can provide heat in the spring or autumn when
the main heating system may not be switched on.
Many LG and Toshiba systems are now available with inverter
driven compressors, which are ideal for domestic applications
because start and run currents are kept every low, often allowing
systems to run off a 13 amp ring main.
See also our CentreCool
website.
|
| |
|
|
Q)
|
Do you have any training courses on air conditioning equipment?
|
|
A)
|
Yes. Both LG and Toshiba offer training courses in their
new state-of-the art training centres.
LG: From September 2005 training courses have been
available at the new LG training facility in Slough.
Toshiba: The new Leatherhead training centre, opened
in February 2007, offers a wide range of courses on both split
systems, multis and VRF.
Please contact
us for further information.
|
| |
|
|
Q)
|
What are the particular refrigerant tube requirements
for R410A?
|
|
A)
|
Because of the higher working pressures involved with air
conditioning systems working on refrigerant R410A, it is necessary
to consider the wall thickness of the refrigerant tube used
during installation, particularly on the high side (e.g. the
liquid line).
The wall thickness of the normal soft and half hard copper
tube that we offer in sizes up to and including 7/8"
is also suitable for use with R410A on both the high and low
side. e.g. for liquid and suction lines.
Half hard copper tube in straight lengths from 1.1/8"
upwards may require tubes with a thicker wall than is used
on say R407c (or R22), particularly on the high side. The
British Refrigeration Association has published guidelines
for these larger tubes, which are available if required. Download
BRA Fact Finder Number 7 (27K Acrobat file).
When making a tight radius bend, regard should be given to
the possibility that the wall thickness of the tube on the
outside of the bend may be reduced to an unacceptable level.
This is more likely when using a mechanical tube bender than
a bending spring, as a bending spring does not allow such
a tight radius. To avoid this problem the use of brazed copper
elbows should be considered.
Flare joints are acceptable on R410A provided they are well
made. Use of an eccentric flaring tool, such as the ITE FTE-800
will ensure a high quality flare without weakening the tube.
For further information please visit the BRA
website.
|
| |
|
|
Q)
|
When is a reduced rate of VAT applicable to the installation
of air conditioning system
|
|
A)
|
Please see FAQ - General for
details
|
| |
|
|
Q)
|
Why is it sometimes necessary to add or remove refrigerant
from a pre-charged air conditioning system?
|
|
A)
|
Many systems are supplied pre-charged with a refrigerant
charge (in the outdoor unit) suitable for correct operation
of the system for a given maximum pipe run, for example 7.5m.
If the actual pipe runs on site are longer, additional refrigerant
must be added to the system to ensure correct operation. This
is sometimes called a "trim charge", and is specified
in grams per additional meter of liquid line (expansion line)
pipework above the maximum for which the unit is pre-charged.
For example, if the pipe run separating the indoor unit and
the outdoor unit is 17.5m, the unit is pre-charged for 7.5m,
and the trim charge is 25g/m (this information is usually
found in the installation manual) then the additional refrigerant
that needs to be added is:
17.5 - 7.5 = 10, x 25 = 250 grams
When pipe runs are very short, for example 2m or less, it
is often recommended that charge is removed. The calculation
is the same as before, but removing refrigerant. For example,
if the liquid line pipe run is 1m, the manufacturers' minimum
pipe run for the pre-charge is 2.5 m, and the trim charge
is 25g/m (use the same trim charge figure as for extending
pipe runs), then the refrigerant that needs to be removed
is:
2.5 - 1 = 1.5, x 25 = 39 grams.
Our technical department will assist with charge calculations
if necessary.
|
| |
|
|
Q)
|
What do the alarm codes displayed by an LG or Hitachi
air conditioner mean?
|
|
A)
|
These indicate a fault with the system, and so assist with
diagnosis.
|
| |
|
| |
|
