HIdRos WDH 039, Техническое руководство

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WDH
Ground source heat pumps
MTWDHGB REV.072008
37
Refrigerant charge checking
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After few hours the unit is working, check that sight glass shows a green colour core: if the core is yellow moisture would be
present in the circuit. In this case it is necessary circuit dehydration to be carried out by qualified people only. Check that at the sight
glass there is no continuous vapour bubbles presence. In this case additional refrigerant charge could be required. It is however
allowed the presence of few vapour bubbles.
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Check that refrigerant superheat on the evaporator is about 5-7 °C
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Check if refrigerant sub-cooling on the condenser is about 5-7 °C.
Unit switch OFF
Please refer to the microprocessor manual enclosed with the unit.
WARNING: Never switch off the unit (for temporary stop), by opening the main switch: this component
should be used only to disconnect the unit from power supply when the current is not passing through,
i.e. when the unit is in OFF mode. Moreover, with no supply to crankcase heater, at the unit start up,
compressor could be seriously damaged.
MAINTENANCE AND PERIODIC CHECKS
WARNING: All operations described in this chapter MUST BE DONE BY TRAINED PEOPLE ONLY. Before
every operation of servicing on the unit, be sure that the electric supply is disconnected. The top shell
and discharge line of compressor are usually at high temperature level. 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 servicing operation close the unit with cover panels, fixing
them with locking screws.
It is a good rule to carry on periodic checks in order to verify the correct operation of the unit.
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Check that safety and control devices work correctly as previously described (monthly).
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Check all the terminals on the electric board and on the compressor are properly fixed. Periodic cleaning of the sliding terminals
of the contactors should be done.
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Verify refrigerant charge checking sight glass (monthly).
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Check there is no oil leakage from compressor (monthly).
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Check there is no water leakage in the hydraulic system (monthly).
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If the unit is to be expected to be stopped for a long period, unit hydraulic circuit should be emptied from all the tubes and heat
exchanger. This operation is compulsory if, during seasonal stop, ambient temperature is expected to go down below the freezing
point of employed mixture (typical seasonal operation).
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Check flow switch proper working (monthly).
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Check compressor crankcase heater proper supply and functioning (monthly).
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Clean metallic filters on water pipings (monthly).
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Check the colour of the sight glass core (green=no moisture, yellow=moisture present): if it has a yellow colour, change the
refrigerant filter (every 4 months).