Water Filling - Hitachi YUTAKI S COMBI Series Installation And Operation Manual

◆ Additional DHW Circuit recommendation
In places where possible hard water areas, to prevent and minims scale situations, it is
recommended to reduce stored water temperature to a maximum of 55°C, as huge scale quantity
could damage the water tank and the electrical heater.
Flush the domestic water circuit with at least 10 times its volume of water. The life of the water
tank will be shorter if groundwater (spring water, well water, etc..) is used without treatment which
can lead to the corrosion of the tank. The water must not be aggressive or encrusting at any time.
The result of calculating the Langelier Index should be between +/- 0.5.
In installation locations where the result of Langelier Index calculation are out of the expected
value with a tendency to corrosive water, it is recommended to install the active anode accessory
(ATW-CP-05).
In the regions where the water is very hard (or out of requirements values) or where the result
of Langelier Index calculation are out of expected value with a tendency to hard water, it is
recommended fitting a softener system. Please ensure that softener system will be capable of
providing effective protection against corrosion. It is recommended to install the active anode
accessory (ATW-CP-05).
As DHW Tank water is being used for storing drinking water, this water has to be in accordance
with national regulations and Hitachi's quality minimum requirements. The use of softeners, active
anodes or others protective systems will not bring a derogation from Hitachi's provided warranty.
5.3.2.1 Water filling
◆ Space heating
1 Check that a water check valve (ATW-WCV-01 accessory) with a shut-off valve (field supplied)
is connected to the water filling point (water inlet connection) for filling the space heating
hydraulic circuit (see
2 Make sure all the valves are open (water inlet/outlet shut-off valves and the rest of valves of the
space heating installation components).
3 Ensure that the air purgers of the indoor unit and installation are open (turn the indoor unit air
purger twice at least).
4 Check that the drain pipes connected to the safety valve (and to the drain pan in case of
installing the "Cooling kit" accessory) are correctly connected to the general draining system.
The safety valve is later used as an air purging device during the water filling procedure.
5 Fill the space heating circuit with water until the pressure displayed on the manometer reaches
approximately 1.8 bar.

NOTE
While the system is being filled with water, it is highly recommended to operate the safety valve
manually so as to help with the air purging procedure.
PMEN0645 rev.0 - 04/2023
"5.4 Space heating and DHW").
5
25