Hydraulic Circuit Checking (Space Heating And Dhw) - Hitachi YUTAKI S COMBI Series Installation And Operation Manual

• Check to ensure that the switch on the main power source has been ON for more than 12 hours,
in order to give the oil heater time to warm the compressor.
• In three-phase unit check phase sequence connection on terminal board.
• Check the power supply voltage (±10% of the rated voltage).
• Check that field-supplied electrical components (main switches, breakers, wires, conduit
connectors and wire terminals) have been properly selected according to the electrical
specifications given in this document, and check that the components comply with national and
local standards.
• Do not touch any electrical components for more than three minutes after turning OFF the main
switch.
• Check the dip switch settings of the indoor unit and the outdoor unit are connected as shown in
the corresponding chapter.
• Check to ensure the electrical wiring of the indoor unit and the outdoor unit are connected as
shown in the chapter.
• Check to ensure the external wiring is correctly fixed. To avoid problems with vibrations, noises
and cut out wires with the plates.
8.2.3 Hydraulic circuit checking (space heating and DHW)
• Check that the circuit has been properly flushed and filled with water and that the installation
has been drained: the pressure of the heating circuit must be 1.8 bar.
• Check for any leakage in water cycle. Pay special attention to the water piping connections.
• Make sure the system's internal water volume is correct.
• Check that the hydraulic circuit's valves are fully open.
• Check to see that electrical heater is completely filled with water by operating pressure of safety
valve.
• Check to see that additional water pumps (WP2 or/and WP3) are correctly connected to
terminal board.
!
CAUTION
• Operating the system with closed valves will damage the unit.
• Check to see that air purge valve is open and that the hydrau lic circuit is air purged. The installer
is responsible of com pletely air purging the installation.
• Check that the water pump of the space heating circuit works within the pump operating range
and that the water flow is over the pump's minimum. If the water flow is under 12 litres/minute
for 4.0-10.0HP (6 litres/minute for 2.0/2.5/3.0HP unit) (with flow switch tolerance), alarm will be
displayed on the unit.
• Remember that water connection must be accordance with local regulations.
• Water quality must comply with EU directive 98/83 EC.
• Electrical heater operation when not completely filled with water will damage the heater.
PMEN0645 rev.0 - 04/2023
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