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70
8. SYSTEM DESIGN GUIDE
WR2-Series-575V
System example of water circuit
4) Piping system
The following items should be kept in your mind in planning / designing water circuits.
a) All units should be constituted in a single circuit in principle.
b) When plural numbers of the water heat source CITY MULTI unit are installed, the rated circulating water flow rate
should be kept by making the piping resistance to each unit almost same value. As an example, the reverse return
system as shown below may be employed.
c) Depending on the structure of a building, the water circuit may be prefabricated by making the layout uniform.
d) When a closed type piping circuit is constructed, install an expansion tank usable commonly for a make-up water tank
to absorb the expansion/contraction of water caused by temperature fluctuation.
e) If the operating temperature range of circulation water stays within the temperature near the normal temperature (sum-
mer :30°C [86°F], winter :20°C [68°F]), thermal insulation or anti-sweating work is not required for the piping inside
buildings.
In case of the conditions below, however, thermal insulation is required.
• When well water is used for heat source water.
• When piped to outdoor or a place where freezing may be caused.
• When vapor condensation may be generated on piping due to an increase in dry bulb temperature caused by the
entry of fresh outdoor air.
Heat
source
unit
BC controller
Backflow prevention valve
Pump
Strainer
3-way valve
3-way valve
Cooling tower
Heating tank
Flexible joint
Refrigerant piping
Refrigerant piping
To indoor unit
Valve
Joint
Drain
Y-shape strainer
Heat
source
unit
BC controller
Heat
source
unit
BC controller
Heat
source
unit
BC controller
0000006382.BOOK 70 ページ ２０２１年７月１９日 月曜日 午後４時１４分
