MEX VS
Chillers and inverter air / water heat pumps with axial fans
18
WARNING: The unit must be connected to the electrical network and should be in STAND-BY mode (powered) closing
the general switch in order to operate the crankcase heaters of the compressor for a minimum of 12 hours before
start up. (the heaters are automatically powered when the main switch is switched off). The crankcase heaters are
working properly if, after some minutes, the temperature of crankcase’s compressor is about 10°C ÷ 15°C higher than
ambient temperature.
WARNING: The weight of the pipes doesn’t load unit structure.
WARNING: Never switch off the unit (for a temporary stop) by switching off the main switch: this component should
be used to disconnect the unit from the power supply only for lengthy stoppages (e.g. seasonal stoppages). Besides,
failing the power supply, the crankcase’s heaters are not supplied thus resulting in a possible breakdown of the
compressors once the unit is switched on.
WARNING: Do not modify the internal wiring of the unit otherwise the warranty will terminate immediately.
WARNING: The summer/winter operating mode have to be selected at the beginning of the related season. Frequent
and sudden changes of this seasonal operating mode have to be avoided in order to prevent severe damages to
compressors.
WARNING: When you first install and start-up the unit make sure that the unit is working properly in both cooling
and heating modes.
9
SHUTDOWNS FOR LONG PERIODS
The types of shutdown depends on the weather of the site where the unit is installed and on the period of the stop. The antifreeze
system, if it’s installed, stay on work also with the on-board control unit in “OFF” position.
If the time of stop is long and the temperature is low, we recommend to drain the hydraulic circuits or use a mixture of water and
glycol.
Drain the hydraulic circuits and shutdown the unit with this passage:
Turn off the unit by placing the switch of each unit to "OFF" position.
Close the water valves.
Place the general differential circuit breaker on "OFF" position, if it is installed upstream of the system.
If the temperature drops below 0°C there is serious danger of frost: add a mixture of water and glycol in the
plant, otherwise drain the hydraulic circuits of the plant and of the heat pump.
WARNING: the operation, although it was transient, with water temperatures below +5°C is not guaranteed on
the basis of the limits set out in Paragraph 15.4. Before you turn the unit on after a long off period, make sure
that the temperature of the mixture of water and glycol is higher than or at least equal to + 5°C.
10
MAINTENANCE AND PERIODICAL CONTROLS
WARNING: All the operations described in this chapter HAVE TO BE CARRIED OUT BY TRAINED STAFF ONLY.
Before any operation or before entering the inner components of the unit, be sure that the power supply is
disconnected. The compressor’s heads and discharge piping are usually at high temperature levels. Be very
careful when operating in their surroundings. Aluminium coil fins are very sharp and can cause serious wounds.
Be very careful when operating in their surroundings. After maintenance operations, re-install the cover panels,
and fix them by means of screws.
The refrigerant circuits must not be filled with different gas other than that indicated on the nameplate. The use
of a different refrigerant can cause severe damage to the compressor.
It’s forbidden to use oils other than those specified in this manual. The use of a different oil can cause serious
damage to the compressor.
The temperatures of heads and discharge piping of the compressor are usually high.
Be careful when working near condensing coils.
The aluminum fins are very sharp and can cause serious injuries.
After the maintenance operations, close the panels tightly with the fastening screws.
Be sure that only trained and qualified personnel to perform maintenance operation and periodical inspections on
the equipment. The EU Regulation 517/2014 establishes that users should assign a qualified personnel to be
responsible to regularly carry out inspections of the facilities, to perform tightness test and elimating eventual
leakages within the shortest possible time. Also has to check the obligatoriness and the necessary documentation
about the Regulation (EU) No 517/2014 and its subsequent amendment or repeal.
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