HIdRos WDH 039, Technical Manual

Page: 36 / 44

WDH
Ground source heat pumps
MTWDHGB REV.072008
36
ELECTRICAL CONNECTIONS
It must be verified that electric supply is corresponding to the unit electric nominal data (tension, phases, frequency) reported on the
label in the front panel of the unit. Power connections must be made in accordance to the wiring diagram enclosed with the unit and
in accordance to the norms in force. Power cable and line protection must be sized according to the specification reported on the
form of the wiring diagram enclosed with the unit.
WARNING: The line voltage fluctuations can not be more than ±5% of the nominal value, while the voltage
unbalance between one phase and another can not exceed 2%. If those tolerances should not be
respected, please contact our Company.
WARNING: Electric supply must be in the limits shown: in the opposite case warranty will terminate
immediately. Before every operation on the electric section, be sure that the electric supply is
disconnected.
WARNING: The Flow switch must be connected following the indication reported in the wiring diagram.
Never bridge the flow switch connections in the terminal board. Guarantee will be invalidated if flow
switch connections are altered or not properly made.
START UP
Before start-up
•
Check that all power cables are properly connected and all terminals are hardly fixed.
•
The voltage at the phase R S T is the one shown in the unit labels.
•
Check that there is not any refrigerant leakage.
•
Check that crankcase heaters are powered correctly.
•
Check that all water connections are properly installed and all indications on unit labels are observed.
•
The system must be bleed off in order to eliminate any air.
•
Before proceeding to start up check that all the cover panels are re-located in the proper position and locked with fastening
screws.
WARNING: Crankcase heaters must be powered at least 12 hours before start up by closing the main
switch (heaters are automatically supplied when main switch is closed). The crankcase heaters are
working properly if after some minutes the compressor crankcase temperature is about 10÷15°C higher
than ambient temperature
Start up
Please refer to the microprocessor manual enclosed with the unit.
If the unit should not start:
•
Check that the control thermostat is set to the correct value.
WARNING: Do not modify internal wiring of the unit otherwise warranty will terminate immediately.
WARNING: In the reverse cycle versions, the summer/winter operation must be selected at the beginning
of the related season. Frequent change over of the seasonal operation mode must be avoided in order to
prevent severe damage to compressors.