Start-Up; Pressure Switch; Avoiding Slugging; Filter Dryer - Danfoss BOCK HRX CO2 T H Translation Of The Original Instructions

6 | Commissioning

6.6 Start-up

Check that the safety and protection devices (pressure switch, motor protection, electrical contact
protection measures, etc.) are functioning properly.
Switch on the compressor and let it run for at least 10 minutes.
The machine should reach a state of equilibrium.
Check the oil level: The oil level must be visible in the sight glass.
After a compressor is replaced, the oil level must be checked again.
ATTENTION If larger quantities of oil have to be topped up, there is a risk of oil

6.7 Pressure switch

Suitably adjusted pressure switches according to EN 378 or a corresponding safety standard that
switch off the compressor before reaching the maximum permissible operating pressure must be
installed in the system. The pressure reduction for the pressure switches can occur either at the
suction and pressure lines.
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6.8 Avoiding slugging

GB
ATTENTION Slugging can result in damage to the compressor and cause
F
E
To prevent slugging:
The complete refrigeration plant must be properly designed.
All components must be compatibly rated with each other with regard to output (particularly the
evaporator and expansion valves).
Suction gas superheating at the compressor input should be > 10 K (check the setting of the
expansion valve).
Regard oil temperature and pressure gas temperature. (The pressure gas temperature has to be
high enough min. 50 °C, so the oil temperature is > 30 °C).
The system must reach a state of equilibrium.
Particularly in critical systems (e.g. several evaporator points), measures such as the use of liquid
traps, solenoid valve in the liquid line, etc. are recommended.
There should be no movement of refrigerant in the compressor while the system is at a
standstill.

6.9 Filter dryer

Gaseous CO
2
it can therefore cause blocking of valves and filters due to ice or hydrate. For this reason we recom-
mend the use of an adequately sized filter drier and a sight glass with a moisture indicator.
20 | AQ452531257528en-000201
impact effects. If this is the case, check the oil return!
refrigerant to leak.
has a significantly lower solubility in water than other refrigerants. At low temperatures
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