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2.9. INSTRUCTIONS FOR FINE TUNING AND GENERAL REGULATION
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 safety valve
High pressure switch (PA)
Low pressure transducer (triggers low pressure alarm, see Electronic Control Manual coupled to the unit)
Water differential pressure switch
Pressure switch
high pressure
water differential
High pressure safety valve
DANGER!
The safety valve on the high pressure side is calibrated at 45 bar. It can intervene if the calibration value is reached while the refriger-
ant is being filled, causing a burst that could cause burns (just like the other valves of the circuit).
Operation of components
Compressor functioning
With the unit off, the oil level in the compressors must be visible though the sight-glass. Topping-up of the oil can be carried out after pumping-out the
compressors, using the pressure connection on the compressor inlet. Once the integral 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). This power circuit pro-
tective device is managed by the microprocessor controller. After it has tripped and been reset, the alarm must be reset on the control panel. It is recom-
mended to remote a light/LED signalling when the protections for each compressor have tripped.
Operation of work, antifreeze and pressure probes
Temperature probes are inserted inside a socket in contact with conductive paste and externally sealed with silicon:
one is placed at the entrance of the heat exchanger and measures the temperature of the return water from the system;
the other one is placed at the evaporator outlet and acts as work and antifreeze probe.
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 dia-
gram 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 paying attention to not damage it in the process. Pay attention when repositioning the probe,
by applying conducting paste in the socket, placing the probe and applying silicon on the external parts so to block it. In the event the antifreeze alarm
triggers, reset the alarm from the control panel; the unit starts only when the water temperature exceeds the intervention differential. The exhaust temper-
ature probes are inserted inside a special sump welded externally to the delivery pipe of both compressors. These probes signal to the electronic board
abnormal increases in the exhaust temperature, generating a thermal protection alarm.
Pressure probes (transducers) are installed:
on the branch of high pressure
it measures the high pressure by generating its alarms and activating and activating its protections. Adjust the summer operation condensation control.
on the low pressure branch
it measures the low pressure generating the relative alarms and the relative protections. They manage the behavior of the electronic expansion valve,
generate the low pressure alarm and regulate the evaporation control in winter operation.
Electronic thermostatic valve functioning
The electronic thermostatic expansion valve is controlled to maintain adequate sub-cooling of the liquid and a correct level of refrigerant in the evaporator.
The operator is not called upon to perform calibration since the control software of the valve monitors these operations automatically.
Functioning of PA: high pressure switch
After the pressure switch has been triggered, it must be reset manually by pressing the black button on the pressure switch itself completely and reset the
alarm from the control panel. Refer to the Troubleshooting section to detect the problem and carry out the necessary maintenance.
2.10. MAINTENANCE
IMPORTANT!
Maintenance is reserved exclusively for skilled personnel from workshops authorised by HITECSA, qualified to operate on this type
of products. Pay close attention to the danger signs on the unit. Use the personal protective equipment foreseen by current laws.
Pay the utmost attention to the symbols located on the unit. Use EXCLUSIVELY original HITECSA. spare parts.
IMPORTANT!
Always adopt personal protective equipment required by law (glasses, headphones, gloves, etc.).
DANGER!
Always use the general circuit breaker protecting the entire system before carrying out any maintenance work on the unit, even if it is
for inspection purposes only. Lock the general circuit breaker in the zero position to make sure that no one accidentally powers the
machine.
IOM_EQRU-SS_EQRHU-SS_2160a4350_208676_230601_ES-EN-FR-DE-IT
97
Intervention
Reset
44 bar
36 bar - Manual
27 mbar
50 mbar - Automatic
48 bar
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