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Startup procedure
Turning on the machine
1. With the general switch Q10 closed, check that switches Q0, Q1 and Q12 are in the Off (or 0) positione.
2. Close the thermal-magnetic switch Q12 and wait for the microprocessor and the control to start. Check that the
oil temperature is warm enough. The oil temperature must be at least 5 °C above the saturation temperature of
the refrigerant in the compressor. If the oil is not warm enough, it will not be possible to start the compressors
and the phrase “Oil Heating” will appear on the microprocessor display.
3. Start the water pump should the machine not be supplied with one.
4. Position the Q0 switch on the On position and wait for Unit-On/ Compressor Stand-By to appear on the display.
If the water pump is supplied with the machine, the microprocessor should start it at this point.
5. Check that the evaporator pressure drop is the same as the design pressure drop and correct it if necessary.
The pressure drop must be measured at the factory-supplied loading joints placed on the evaporator piping. Do
not measure pressure drops in points where any valves and/or filters are interposed.
6. Only at the first startup, position the Q0 switch on Off to check that the water pump stays on for three minutes
before it, too, shuts down (both the on-board pump and any external pump).
7. Move the Q0 switch to On once again.
8. Check that the local temperature setpoint is set to the required value by pressing the Set button.
9. Turn the Q1 switch to On (or 1) to start compressor #1.
10. Once the compressor has started, wait at least 1 minute for the system to start stabilising. During this time the
controller will perform a series of operations to empty the evaporator (Pre -Purge) to ensure a safe startup.
11. At the end of the Pre-Purge, the microprocessor will start loading the compressor, now running, in order to
reduce outgoing water temperature. Check the proper functioning of the loading device by measuring the
compressor’s electrical current requirement..
12. Check refrigerant evaporation and condensation pressure.
13. Check that the cooling ventilators have started, in relation to and increase in condensation pressure.
14. Check that, after the time required for the refrigerant circuit to stabilise, the liquid pilot lamp located on the tube
leading into the expansion valve is completely full (no bubbles) and that the hu
midity indicator shows “Dry”. The
passage of bubbles inside the liquid pilot lamp could indicate a low refrigerant level or an excessive pressure
drop through the dehydration filter or an expansion valve that is blocked at the maximum open position.
15. In addition to checking the liquid pilot lamp, check the circuit operating parameters by verifying:
-
Compressor overheating during intake
-
Compressor overheating during exhaust
-
Undercooling of liquid coming out of the condenser batteries
-
Evaporation pressure
-
Condensation pressure
Except for liquid temperature and intake temperature for machines with a thermostatic valve, whcih require the use of an
external thermometer, all other measurements can be carried out by reading the relevant values directly on the on -
board microprocessor display.
Table 25 - Typical working conditions with compressors at 100%
Economised cycle?
Suction superheat
Discharge
superheat
Liquid Subcooling
NO
4
6 °C
20
25 °C
5
6 °C
SI
4
6 °C
18
23 °C
10
15 °C
NB: Typical working condition are for unit working at about 2° suction saturated temperature and about 50°C saturated
discharge temperature
IMPORTANT
The symptoms of a low refrigerant charge are: low evaporation pressure, high intake and exhau st overheating (beyond
the above limits) and a low undercooling level. In this case, add R134a refrigerant to the relevant circuit. A loading joint is
foreseen in the system, between the expansion valve and the evaporator. Charge refrigerant until working conditions
return to normal.
Remember to reposition the valve cap when finished.
To turn off the machine temporarily (daily or weekend shutdown) turn the Q0 switch to Off (or 0) or open the remote
contact between terminals 58 and 59 on terminal board M3 (Installation of remote switch to be carried out by the
customer). The microprocessor will activate the shutdown procedure, which required several seconds. Three minutes
after the compressors have been shut down, th microprocessor will shut down the pump . Do not switch of the main
power supply so as not to de-activate the electrical resistances of the compressors and of the evaporator.
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