Hitachi YUTAKI RWM-2R1E Installation & Operation Manual page 74

REFRIGERANT AND WATER PIPING
8 If a little quantity of air is still remaining in the water circuit, it will be removed by the automatic air purger of the indoor unit during
the first hours of operation. Once the air in the installation has been removed, a reduction of water pressure in the circuit is very
likely to occur. Therefore, additional water should be filled until water pressure returns to an approximate level of 1.8 bar.
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N O T E
• The indoor unit is equipped with an automatic air purger (factory supplied) at the highest location of the indoor unit. Anyway, if there are higher
points in the water installation, air might be trapped inside water pipes, which could cause system malfunction. In that case, additional air purgers
(field supplied) should be installed to ensure no air enters into the water circuit. The air vents should be located at points which are easily accessible
for servicing.
• The water pressure indicated on the indoor unit manometer may vary depending on the water temperature (the higher temperature, the higher
pressure). Nevertheless, it must remain above 1 bar in order to prevent air from entering the circuit.
• Fill in the circuit with tap water. The water in the heating installation must comply with EN directive 98/83 EC. Non-sanitary controlled water is not
recommended (for example, water from wells, rivers, lakes, etc.)
• The maximum water pressure is 3 bar (nominal opening pressure of the safety valve). Provide adequate reduction pressure device in the water
circuit to ensure that the maximum pressure is NOT exceeded.
• For heating floor system, air should be purged by means of an external pump and an open circuit to prevent the formation of air pockets.
• Check carefully for leaks in the water circuit, connections and circuit elements.
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Domestic hot water tank
If a domestic hot water tank has been installed, perform the following operations:
Heating coil circuit
Fill the DHW tank heating coil from the space heating circuit filling in point. Follow the instructions explained in the
filling" chapter to correctly perform the operation.
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C A U T I O N
• Check that the heating coil pipes are correctly connected between indoor unit and tank before filling the tank's heating coil.
• Ensure the correct water quality of the indoor unit water circuit.
Domestic hot water tank and DHW circuit
1 Open the outlet water taps of the DHW installation one after each other, to expel all the air from inside the water circuit.
2 Open the main DHW inlet valve in order to fill the tank. If there is a shut-down valve installed in the DHW outlet, open it to allow
circulation through the DHW installation.
3 When water begins to flow from the outlet water taps of the DHW installation, close all these taps.
4 Finally, close the main DHW inlet valve when the pressure reaches approximately 6 bars.
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C A U T I O N
• Check carefully for leaks in the water circuit, connections and circuit elements.
• Check that the water pressure in the circuit is lower than 7 bars.
• A pressure and temperature relief valve should be installed at the DHW inlet connection (See
(For DHW)" section). If it is the case, manually operate its relief valve to ensure that the water flows free through the discharge pipe.
• Fill in the circuit with tap water. The water in the heating installation must comply with EN directive 98/83 EC. Non-sanitary controlled water is
not recommended (for example, water from wells, rivers, lakes, etc.)
60 PMML0575 rev.2 - 03/2022
Water
pump
ON
DHW
3Wv
OFF
Repeat...
Seconds
Repeat...
Seconds
"6.5.3.1 Water
"6.7.2.3 Additional hydraulic optional elements