Hitachi YUTAKI S80 Serie Manuel D'instructions page 31

MAINTENANCE
9.2 COMMISSIONING PROCEDURE
• When installation is complete and all necessary settings
(Dip-switches in PCBs and User interface configuration)
have been carried out, close the E.BOX and place the
cabinet as shown in the manual.
10 MAINTENANCE
!
C A U T I O N
All the following operations must be done by a licensed technician.
10.1 GENERAL PROCEDURE
To ensure good operation and reliability of the DHW tank its
main parts and field wiring have to be checked periodically.
!
C A U T I O N
• All inspections and checks of the DHW tank have to be carried out by
a licensed technician and never by the user itself.
• Before any inspection and check the DHW tank main power supply
has to be switched OFF. In this case, the indoor unit supply has to be
switched OFF.
• Make sure that the outdoor unit main power supply is also switched
OFF before any operation or repair.
The following checks have to be done by qualified technicians at
least once a year:
1 Domestic Hot Water flow and pressure: check that the water
circulation is correct along all the DHW circuit and that there
is no loss of pressure and water flow.
2 Water leakage: check that there are no water leakages in
the main water circuit. Check all the joints, connections and
circuit elements.
10.2 DESCALING
Water quality and set temperature can affect the scale production
and it can deposit on the heating coil surface of the DHW tank
restricting the heat exchange and the good operation of the unit.
?
N O T E
Descaling should be necessary periodically at certain intervals depending
on the supplied water quality.
Check the scale level when proceeding maintenance to ensure
reliability of the unit.
23 PMML0344B rev.2 - 01/2021
• Select the heating operation mode in the Unit controller.
• Make a test run as shown in item Indoor unit test run.
• After test run is completed, start the entire unit or the
selected circuit by pressing the Run/Stop button.
3 Security water valve: check the correct operation of the
security water valve (pressure relief valve) on the DHW tank
water circuit.
4 Fixing points tightening: check the fixing points of the DHW
tank. In case tank over indoor unit option, check the joints
between the tank and the indoor unit. In case tank beside
indoor unit option, check the DHW tank mounting foots. The
tank has to be always in a vertical position and well fixed
to the wall with the required Wall fixing accessory providing
higher stability.
?
N O T E
All these maintenance operations must be done with appropriate materials
and following this manual.
If necessary, proceed with descaling:
1 Switch OFF the main power supply of the indoor unit.
2 Empty the DHW tank of water as explained in
section.
3 Proceed with descaling of the heating coil.
4 Ensure that the water quality remains compliant with the EU
council directive 98/83 EC.
"10.3 Draining"