System Pump Down - Airwell DK 125 Manual De Instalación Y De Mantenimiento

SYSTEM PUMP DOWN

The 125, 155 and 185 outdoor units are supplied pre-filled with their refrigerant fluid charges. It is necessary to
pump down the piping as well as the indoor unit and to conduct a leakage test before opening the Flare valves.
Follow the instructions below for vacuum draining and leakage detection. Adjust the refrigerant charge accordingly
(refer to § refrigeration specifications) for pipe lengths other than stated on the unit's maker's plate,.
The 205, 255, 305, 405m, 405, 505, 605, 755 and 905 units are supplied filled with nitrogen. It is imperative
to drain the nitrogen charge, then vacuum drain the entire system and finally check for the absence of leaks prior
to proceeding with filling the system with refrigerant fluid.
In no event should the compressor be used to pump dow the system. It is not designed for
this usage and serious damage may result.
A vacuum pump must be used for system pump down. Connect the pump to the service taps on either side of the
compressor.
Start the vacuum pump and let it run until the pressure level in the system is below 10-1 mbar, as this pressure is
sufficiently low to remove humidity.
If this pressure level cannot be achieved, check the capacity of the pump and the entire system for any possible
leakages.
When the system has been pumped down, allow it to remain at this level of vacuum for a period of 12 hours. If no
significant rise in pressure occurs, the system is ready to be filled with the refrigerant charge.
The bottle of refrigerant must be connected to the Hp service tap on the liquid pipe. A dryer placed as near as
possible to the service tap on the liquid pipe must be used when charging the refrigerant . In the case of R407C,
ensure that the charge is filled in liquid form. The vacuum created in the indoor and outdoor units causes a
considerable quantity of refrigerant to enter the system.
The charges are indicated (refer to § refrigeration specifications) for 4 metre pipe lengths between the indoor and
outdoor units and are provided for information purposes only. The filling operation must continue until 80% to 90%
of the indicated charge has entered the system (corrected for pipe lengths other than 4 metres).
Start the system. The outdoor and indoor temperatures should be as close as possible to actual operating conditions.
Continue to add refrigerant until the refrigerant passing under the liquid inspection glass is "clear". In this event,
the refrigerant is entirely in liquid form. Allow the system to operate for about one hour to reach a stable operating
regime.
If necessary, adjust the refrigerant charge in relation to the information provided by the liquid inspection glass and
the measurement of the subcooler temperature. This value is equal to the saturated liquid temperature in relation
to the condensing pressure (refer to the R22 and R407C refrigerant characteristics charts) less the condenser outlet
temperature (liquid line temperature measured with the aid of a thermocouple). The subcooler temperature value
must be between 4°C and 8°C. If bubbles can be seen in the liquid through the liquid inspection glass, refrigerant
needs to be added. A subcooler temperature above 8°C is a sign of overfilling and in this case, refrigerant must
be drained from the system.
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