Before setting the system in a vacuum, it is advisable to make sure that the refrigerant circuit is tight, including the connecting joints between the pipes and the indoor unit.

Proceed in the following way:

• With the service valves of the outdoor unit completely shut, remove the cap from the service tap (part 1 - fig. 12) and the union (part 2 - fig. 12) of the gas valve

(the larger one)

• Connect the service valve to a manometric unit plus oxigen free nitrogen (OFN) bottle.

• Pressurize the system to a maximum 43 bar (44kg/cm

• Use liquid soap to check that the joints are tight and without leaks.

Keep the bottle vertical during the pressurizing operation to prevent liquid nitrogen from infiltrating into the system!

• Check all the connection joints on both the outdoor and indoor units to make sure that they are tight. Bubbles will form if leaks are present. If bubbles appear, make

sure that the unions have been tightened and that the flares are the right shape.

• Wipe off the liquid soap with a rag.

• Reduce the pressure of the nitrogen in the circuit by loosening the charge pipe from the bottle.

• Having reduced the pressure, disconnect the nitrogen bottle.

CAUTION

The airtight testing should never use any oxygen, flammable gas or poisonous gas.

7.4.2 Air purge with vacuum pump

Air and humidity in the cooling circuit impair the operation of the unit with effects such as: increased pressure, reduced efficiency, formation of ice on the capillary and

subsequent blockage of the same, corrosion in the circuit.

This is why a vacuum must be created in the connection pipes and indoor unit.Proceed in the following way:

• Connect the previously described charging pipe to the vacuum pump.

• Turn on the relative knob on the monometric unit to allow the pump to access the cooling circuit.

• Wait until the pressure level measured by the pressure gauge is around 3 mm Hg (400 Pa)

• As soon as the required vacuum value is reached, shut the connection cock and stop the vacuum pump.

Note

OU =

Outdoor unit

IU =

Indoor unit

) using the oxigen free nitrogen (OFN) in the bottle.