When fitting a new air conditioning unit to a property, the installer would normally attach the indoor and outdoor units to there required location. Various types and styles are available which attach to the wall or ceiling.

An electrician will install a power supply which feeds either the indoor evaporator or the outdoor condenser depending upon model. An interconnecting cable is then installed between the two units which enables the indoor unit to control the outdoor unit functions.

Two copper pipes are then installed between the two units. Brazing is used to solder the pipe joints and not plumbers solder. During the brazing process the pipe is flushed with oxygen free nitrogen to ensure no scale builds up inside the pipe when brazed. If scale build up occurs it may break off and block the pipes or permanently damage the compressor.

Final connections of the pipes to the indoor and outdoor units are achieved using a copper flare connection, similar to those found on vehicle break pipes. The flare connection can withstand large pressures and when assembled correctly will not leak.

The pipes are now charged with oxygen free nitrogen under pressure. This pressure is recorded and if it lowers over time there is a leak on the unit.

From experience we recommend that the oxygen free nitrogen remains in the pipes for a minimum of 24 hours. Any changes over this time period can mean only one thing a leak.

When the pipes have been proved and do not leak the nitrogen is removed. The pipes are then connected to a vacuum pump which removes oxygen and condensable gasses such as water vapour from the pipes.

The final stage is to charge the refrigerant into the pipes and then commission the system.

So, can an air conditioning unit be installed in a day? Well, yes it can.

The main problem with a single day installation is the time the pressure test is left for. Some very small leaks will not be detected unless the nitrogen is charged for at least 24 hours. If there is a leak, the refrigerant will leak and eventually the unit will run out of charge.

Its efficiency will slowly degrade until it ceases to function. As the refrigerant also contains lubrication oil for the compressor, it will only be a matter of time until major compressor failure occurs. If this can be attributed to bad installation then any manufacturer warranty will be void.

Our advice is to leave the pressure test for at least 24 hours and use either LG Air Conditioning units, Daikin or Sanyo.

Philip Hamer

Magma Energy Services Ltd