Airedale SmartCool 11-233kW - Manual (Page 171)

Precision Air Conditioning SmartCool
TM
– D
Precision Air Conditioning
171
Installation, Maintenance and Commissioning Manual :6877419 02/2013
Commissioning procedure
Refrigeration circuit
Expansion Valve Record on the commissioning sheet the type of expansion valve fitted to the unit. i.e.
· Electronic Expansion Valve (EEV)
· Thermostatic expansion Valve (TEV)
Pressure Switch Settings Record the design pressure switch settings.
· High pressure Out
· Low pressure In
· Low pressure differential
System Pressure Readings Record on the actual system operating pressures.(Barg)
· Suction pressure
· Discharge pressure
· Liquid pressure
Superheat / Sub cooling Record the superheat and sub cooling readings, typically 6°C superheat and 3°C Sub-
cooling.
Superheat protects the compressor from liquid flood back and the amount of sub cooling
ensures enough liquid refrigerant to enter the expansion device.
Long pipe runs may require additional sub cooling to overcome the pressure drop of
these lines. This could cause the unit to operate at a reduced capacity.
Compressor currents Record on the commissioning sheet the operating currents of the compressor. The
current reading is to be taken when the unit is running at full load.
Sight Glass
Check the condition of the sight glass. References on the commissioning sheet are
· Wet or Dry
· Clear or Bubbles
The sight glass is used to indicate
· the condition of the refrigerant in the system
· lack of sub-cooling
· refrigerant deficiency
· Moisture content of the refrigerant.
The colour of the sight glass depends on the moisture content of the refrigerant. The
recommended moisture levels of a system should be between 30 and 75ppm.
An indication of green/dry are to be considered as perfect conditions meaning full
protection by the filter drier against effects from moisture.
If the green colour starts to fade, the colour change from green to yellow has begun and
the indicator should therefore be watched carefully. If the colour changes to yellow it is a
clear signal that the capacity of the filer drier is exceeded and should be replaced as soon
as possible.
CAUTION Be aware that Polyolester (POE) oil for HFC refrigerants (R134a, R404A, R407C and
R410A) reacts with moisture in a hydrolysis generating acid. Polyolvinyl ether (PVE) oil
does not have the same problem with acid but still requires good refrigeration practice.
Filter Drier The filter drier ensures that any moisture / debris are captured. The drier should be
installed last in any system prior to evacuation. It should be installed as close to the
expansion valve as possible. If the drier is allowed to be in contact with moisture it can be
difficult to evacuate the system; making the installation time longer.
Airedale recommends that a quality filter drier is used to ensure that the performance of
the system is not reduced.
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