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SECTION II: INSTALLATION AND MAINTENANCE
II.8
INSTRUCTIONS FOR FINE TUNING AND
ADJUSTMENTS
II.8.1
Calibration of safety and control devices
The units are tested in the factory, where they are also calibrated and
the default parameter settings are put in. These guarantee that the
appliances run correctly in rated working conditions.
The devices which monitor safety of the unit are the following:
High pressure switch (PA)
Low pressure switch (PB)
High pressure safety valve
Safety component calibration settings
Pressure switch
Tripping
Reset
high pressure
40.2 Bar
28.1 bar - Manual
low pressure
2 bar
3.3 bar
– Automatic
water differential
80 mbar
105 mbar - Automatic
High pressure safety valve
41.7 bar
-
DANGER!
The safety valve on the high pressure side is
calibrated at 41.7 bar. It can intervene if the
calibration value is reached while the refrigerant is
being filled, causing a burst that could cause burns
(just like the other valves of the circuit).
II.8.2
Operation of components
II.8.2.1
Compressor operation
Scroll compressors are equipped with internal circuit breaker protection.
Once the circuit breaker has tripped, normal operation is automatically
resumed when the temperature of the windings drops below the preset
safety value (this can take from a few minutes to several hours).
II.8.2.2
Operation of the work, antifreeze and
pressure probes
The water temperature probes are inserted within a socket in contact
with conductive paste and sealed from the outside with silicon.
One is placed at the inlet of the heat exchanger and measures the
temperature of the return water from the system;
the other is placed at the exit of the evaporator and acts as an
operational and anti-freeze probe in units with no storage tank and only
as an antifreeze probe in units with storage tank.
Always check that both wires are firmly welded to the connector and
that this is properly inserted in the housing on the electronic board (see
wiring diagram provided). In order to verify the efficiency of a 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 not to damage 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 triggered, this must be reset
through the control panel. The unit starts up again only when the water
temperature exceeds the triggering difference.
II.8.2.3
Operation of the thermostatic valve (only for
heat pumps)
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.8.2.4
Operation of the electronic thermostatic
valve
The electronic thermostatic expansion valve is calibrated to maintain
the gas superheated by at least 6K, to avoid any liquid being sucked
into the compressor. The operator is not required to perform calibration
since the control software of the valve monitors these operations
automatically.
II.8.2.5
Operation of the PA: high pressure switch
After the high pressure switch has tripped, it needs to be reset manually
by firmly pressing the black button on the pressure switch itself and
resetting the alarm on the control panel. Refer to the Troubleshooting
section to identify the problem and perform the necessary maintenance.
II.8.2.6
Operation of the PB: low pressure switch
After the low pressure switch has tripped, 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 perform the
necessary maintenance.
Summary of Contents for EQU-PF 2100
Page 60: ...NOTE...
