Lennox INNOV DM R Series Application Manual page 57

9.6 Tightness test
Fill the circuit with anhydrous nitrogen supplied from a tank with a pressure-reducing valve until the pressure rises
to 22 bars.
During the pressurization phase, do not exceed a pressure of 22 bars on the compressor low
pressure side.
The presence of any leaks must be determined using special leak detectors. Should any leaks be detected during
the test, empty out the circuit before repairing the leaks with suitable alloys.
Do not use oxygen in the place of nitrogen as a test agent, since this would cause a risk of
explosion.
9.7 Hard vacuum and drying of cooling circuit
To achieve a hard vacuum in the cooling circuit it is necessary to use a pump capable of generating a high degree
of vacuum, i.e. 150 Pa of absolute pressure with a capacity of approximately 10 m
one evacuation will normally suffice to achieve an absolute pressure of 150 Pa. If there is no such vacuum pump
available, or whenever the circuit has remained open for long periods of time, you are strongly recommended to
adopt the triple evacuation method. This method is also recommended when there is a presence of humidity
within the circuit. The vacuum pump should be connected to the inlets.
The procedure to be carried out is as follows:
·
Evacuate the circuit until you reach an absolute pressure of at least 350 Pa: at this point inject nitrogen into
the circuit until you reach a relative pressure of about 1 bar.
·
Repeat the step described above.
·
Carry out the step described above for the third time, but in this case attempting to reach the hardest vacuum
possible.
Using this procedure you can easily remove up to 99% of pollutants.
9.8 Recharging with refrigerant R410A
· Connect the tank of refrigerant gas to the male 1/4 SAE inlet situated on the liquid line after discharging a
little gas to eliminate air in the connection pipe.
· Fill with refrigerant in liquid form until you reach 75% of the total charge. For monobloc unit (water
cooled), the correct refrigerant charge is shown in silver plate. For split units (air cooled) check
the "Piping design criteria"attached to the unit documentation.
· Then connect to the inlet on the pipe between the thermostatic valve and evaporator and complete the
charging process with the refrigerant in liquid form until no more bubbles can be seen on the liquid level
indicator and the operating parameters specified in section 7.4 have been reached (see piping descign
criteria).
These units are designed for the exclusive use of R410A refrigerant and should not be
charge with different refrigerants without the written permission of the manufacturer.
9.9 Environmental protection
The law implementing the regulations (reg. EEC 2037/00) which govern the use of ozone-depleting substances
and greenhouse gases bans the dispersal of refrigerant gases in the environment and requires whoever is in their
possession to recover them and, at the end of their useful life, either to return them to the dealer or take them to a
suitable waste disposal facility. The refrigerant HFC R410A is not harmful to the ozone layer but is included
among the substances responsible for the greenhouse effect and thus falls within the scope of the aforesaid
regulations.
Therefore, special care should be taken when carrying out maintenance work to minimize
refrigerant leaks.
INNOV@ ECFAN DHR -AGU-0912-E
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/h. If such a pump is available,
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