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14 MAJOR SYSTEM COMPONENTS
14.1 - Compressors
AR05 units use hermetic scroll compressors. Each compressor
is equipped with a crankcase oil heater, as standard.
Each compressor sub-function is equipped with:
•
Anti-vibration mountings between the unit chassis and
the chassis of the compressor sub-function.
•
A single pressure safety switch at the discharge.
14.2 - Lubricant
The compressors installed in these units have a specifi c oil
charge, indicated on the name plate of each compressor.
The oil level check must be done with the unit switched off ,
when then suction and discharge pressures are equalised. The
oil level must be visible and above the middle of the sight-
glass in the oil equalisation line. If this is not the case, there is
an oil leak in the circuit. Search and repair the leak, then
recharge oil, so that it reaches a level between the middle and
three quarters of the sight-glass (unit in vacuum).
ATTENTION: Too much oil in the circuit can cause a unit
defect. R-22 oils are absolutely not compatible with R-410A
oils and vice versa.
NOTE: Use only oils which have been approved for the
compressors. Never use oils which have been exposed to air.
14.3 - Air evaporator/condenser
The AR05 coils are heat exchangers with internally grooved
copper tubes with aluminium fi ns. To prevent ice formation
at the bottom of the coils, electric heaters are installed under
the sheet metal base. They are switched on, based on the
outside temperature.
14.4 - Fans
The fans are axial Flying Bird fans equipped with rotating
shroud and made of composite recyclable material. The
motors are three-phase, with permanently lubricated
bearings and insulation class F.
14.5 - Electronic expansion valve (EXV)
The EXV is equipped with a stepper motor (2625 + 160 /- 0
steps) that is controlled via the EXV board.
14.6 - Moisture indicator
Located on the liquid line, permits control of the unit charge
and indicates moisture in the circuit. The presence of bubbles
in the sight-glass indicates an insuffi cient charge or non-
condensables in the system. The presence of moisture
changes the colour of the indicator paper in the sight-glass.
26
14.7 - Filter drier
This is a one-piece, brazed fi lter drier, located in the liquid
line. The role of the fi lter drier is to keep the circuit clean and
moisture-free. The moisture indicator shows when it is necessary
to change the fi lter drier. The fi lter drier is a bi-fl ow device, that
means that it fi lters and dehydrates in both operating modes.
The pressure drop is much higher in the heating mode. A
diff erence in temperature between the fi lter inlet and outlet
shows that the element is dirty.
14.8 - Water evaporator/condenser
The evaporator/condenser is a plate heat exchanger with one
or two refrigerant circuits. The water connection of the heat
exchanger is a Victaulic connection. It has a thermal insulation
of 19 mm thick polyurethane foam and includes frost
protection, as standard.
The products that may be added for thermal insulation of the
containers during the water piping connection procedure must
be chemically neutral in relation to the materials and
coatings to which they are applied. This is also the case for
the products originally supplied by Danfoss.
NOTES - Monitoring during operation:
•
Follow the regulations on monitoring pressurised
equipment.
•
It is normally required that the user or operator sets up and
maintains a monitoring and maintenance fi le.
•
Follow the control programmes of EN 378-4, annex D.
•
If they exist follow local professional recommendations.
•
Regularly check for possible presence of impurities (e.g.
silicon grains) in the heat exchange fl uids. These impurities
maybe the cause of the wear or corrosion by puncture.
•
The reports of periodical checks by the user or opera-tor
must be included in the supervision and mainte-nance fi le.
14.9 - Refrigerant
AR05 units operate with refrigerant R-410A.
14.10 - High-pressure safety switch
AR05 units are equipped with automatically reset high-
pressure safety switches, calibrated to 4520 kPa (unit alarm is
manually reset).
14.11 - Receiver
AR05 units are equipped with mechanically welded receivers
that permit storing the excess charge when the unit operates
in heating mode.
14.12 - Four-way valve
This permits reversal of the cycle for operation in cooling and
heating mode and during defrost cycles.
Installation, operation and maintenance instructions - VMGFE102
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