Valeo REVO-E, Evacuation And Charging Instructions

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Evacuation of the refrigerant cycle REVO E Evacuation and Charging Instructions
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3 Evacuation of the refrigerant cycle
3.1. Achieved final vacuum
In the entire refrigerant cycle a final vacuum of less than10 mbar must
be achieved. It is also important that the required pressure of less than
10 mbar must be measurable at every point of the refrigerant cycle and
not only at the vacuum pump. Due to the components of the refrigerant
circuit, solenoid valve (must be open), unfavorable for flow service val-
ves, long hoses to vacuum pump, etc., naturally a very large flow re-
sistance arises during evacuation. Therefore, the vacuum should be me-
asured directly in the unit (service connection in the liquid line).
3.2. Evacuation process
The vacuum pump and measuring devices to be used must be in a fault-
less condition. With reference to the documentation of the equipment
make sure that the oil in the vacuum pump is replaced at regular inter-
vals. The vacuum measuring devices must be suitable for the measuring
range. Normally, the equipment is evacuated after service and/or repair
work together with concluding Nitrogen pressure check. The sequence
of the listed points must be followed:
– Before connecting to the vacuum pump the circulation must be
“pressure-less”.
– Open the magnetic valves in the refrigerant liquid line of the rooftop
unit. This can be done through electrical controls with the service
program or permanent magnets which are fixed to the valves instead
of the magnetic coil.
– All blokking valves in the refrigerant cycle (compressor and service
valves) must be opened.
– Depending on the way to charge: with a charging station or manually
with a digital manifold, you must be proceed as follows:
Charging station:
The hoses of the charging station are connected to the service ports
of the compressor. Start the evacuating process according to the
operating instructions of the charging station used.
Charging manually using a digital manifold:
The appropriate hoses (high and low pressure) are connected to the
service ports of the compressor.
– A vacuum pump is connected by means of a large diameter (3/8“)
hose to the digital manifold.
– The achieved vacuum can only be checked by two methods. In the
first method, a suitable vacuum meter is connected while evacuating
at the farthest point of the refrigerant cycle. The second and consi-
derably safer method is to block the vacuum pump, wait until there is
a pressure balance in the refrigerant cycle and then to measure the
achieved vacuum in the system.
– After balancing the pressure the vacuum in the refrigerant cycle must
be still <10 mbar.
Causes for not achieving vacuum
The following causes may be present if the required vacuum is not
achieved:
– If moisture is present within the circulation a vapor pressure of
approx. 23 mbar sets in at 20 °C ambient temperature.
– If the oil temperature is > 60 °C vapor pressure in the refrigerant cy-
cle settles above 1 mbar.
– There may be leakages between vacuum pump and the service con-
nections.
– The refrigerant cycle was evacuated with opened gas ballast of the
vacuum pump.