II.9.3.6 Check and restore the compressor's oil
charge
With the unit switched off, the oil level in the compressors must partially
cover the sight-glass on the level matching tube. The level is not always
constant as it depends on the ambient temperature and the percentage
of refrigerant in oil.
With the unit on and in nominal conditions the oil level must be clearly
visible through the sight-glass on the level matching tube and must be
flat without any ripples.
An additional topping-up of the oil can be carried out after pumping-out
the compressors, using the pressure connection on the compressor
inlet. For information on the amount and type of oil refer to the label on
the compressor or contact a EMMETI S.p.A. service centre.
II.9.3.7 Compressor operation
Scroll compressors are equipped with internal thermal protection.
Once the thermal protection has been activated, normal operation is
automatically resumed when the windings temperature drops below the
pre-set safety value (this can take from a few minutes to several hours).
II.9.3.8 Operation of working, antifreeze and pressure
probes
Temperature probes ST1, ST2, ST4 are inserted within a socket in
contact with a conductive paste and sealed from the outside with
silicon.
•
Probe ST1 is placed at the entrance of the heat exchanger and
measures the temperature of the return water from the system;
•
Probe ST2 is placed at the exit of the evaporator and acts as an
operational and antifreeze probe in units with no water buffer tank and
only as an antifreeze probe in units with water buffer tank;
•
Probe ST4 is placed at the exit of the water buffer tank and acts as
an operational probe in units with water buffer tank.
Always check that both the wires are firmly welded to the connector and
that this is properly inserted in the housing on the electronic board (see
the electrical wiring diagram provided). In order to check the efficiency
of the probe use a precision thermometer immersed with the probe in a
container full of water at a certain temperature after having removed the
probe from the socket taking care to avoid damaging it in the process.
The probe must be carefully repositioned by placing some conductive
paste in the socket, inserting the probe and re-sealing the external part
with silicon to avoid unscrewing. If the antifreeze alarm is activated this
must be reset through the control panel. The unit starts up again only
when the water temperature exceeds the triggering difference.
The pressure probe (BP1) is screwed onto a connection situated on the
high pressure pipe. Check that the connectors on the board and on the
probe are inserted. Check efficiency of the probe by comparing the
display reading with the reading of the pressure indicated by a gauge
connected to the high pressure pipe.
SECTION II: INSTALLATION AND MAINTENANCE
II.9.3.9 Operation of thermostatic valve (VTE/VTI)
The thermostatic expansion valve is calibrated to maintain the gas
superheated by at least 6°C, to avoid any liquid being sucked into the
compressor.
If the superheating setting needs to be changed, adjust the valve as
follows:
•
turn in an anticlockwise direction to reduce superheating;
•
turn in a clockwise direction to increase superheating.
Remove the screw cap on the side of the valve and then turn the
adjustment screw using a screwdriver. By increasing or decreasing the
amount of refrigerant, the superheating temperature value is either
decreased or increased. The temperature and pressure inside the
evaporator remains more or less the same, regardless of changes to
the thermal load.
After any adjustments to the valve it is advisable to allow a few minutes
to elapse to give the system the chance to re-stabilise.
II.9.3.10 Operation of high pressure switch (PA)
After the high pressure switch has been activated, it needs to be reset
manually by firmly pressing the black button on the pressure switch
itself. Then reset the alarm at the control panel. Refer to the
Troubleshooting section to identify the problem and carry out the
necessary maintenance.
II.9.3.11 Operation of low pressure switch (PB)
After the low pressure switch has been activated, the alarm must be
reset at the control panel; the pressure switch is reset automatically, but
only when the suction pressure reaches the set differential value. Refer
to the Troubleshooting section to identify the problem and carry out the
necessary maintenance.
II.10
DISMANTLING THE UNIT - DISPOSAL OF
HARMFUL COMPONENTS/SUBSTANCES
ENVIRONMENTAL PROTECTION
Dispose of the packaging materials in compliance
with the national or local legislation in force in your
country. Do not leave the packaging within reach of
children.
It is advisable that the dismantling of the unit is performed by a
company authorised to collect obsolete products and machinery.
The unit as a whole is composed of materials which can be treated as
SRM (secondary raw materials) and the following conditions must be
observed:
• the oil contained in the compressor must be removed. It must be
recovered and consigned to an authorised waste oil collection firm;
• refrigerant gas may not be discharged into the atmosphere. It should
instead be recovered by means of homologated devices, stored in
suitable cylinders and delivered to a company authorised for the
collection;
• the filter drier and electronic components are to be considered
special waste and as such they must be delivered to a company
authorised for the collection;
• The expanded polyurethane insulation to the water exchangers must
be removed and processed as urban-type waste.
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