Toshiba HWS-803XWHM3-E Installation Manual page 16

Hydro Unit
Piping to hot water cylinder (option)
Water supplied to the hot water cylinder is branched by
a motorized 3-way valve (locally procured).
For the specifications of the motorized 3-way valve,
refer to "Control parts specifications" on page 21.
Connect the hot water cylinder to port A (open when
energized) of the valve.
▼ Fig. 7-13
to hydro unit
room heating or cooling
Open when de-
B
energized
Piping to 2-zone operation
To perform 2-zone temperature control, circulate water
by another pump (locally procured) through a
motorized mixing valve (locally procured) and a buffer
tank (locally procured).
For the specifications of the motorized mixing valve,
Refer to "Control parts specifications" on page 21.
▼ Fig. 7-14
Motorized mixing valve
(locally procured)
Water pump
(locally procured)
Zone
2
Buffer tank (locally
procured)
Checking water volume and initial pressure
of expansion vessel
The expansion vessel of the Hydro Unit has a capacity
of 12 liters.
The initial pressure of the expansion vessel is 0.1 MPa
(1 bar).
The pressure of the safety valve is 0.3 MPa (3 bar).
Verify whether the capacity of the expansion vessel is
sufficient using the following expression. If the volume
is insufficient, add the capacity locally.
15-EN
to hot water cylinder
AB
A Open when energized
from hydro
unit
A
AB
B
to hydro unit
– 16 –
Expression for expansion vessel selection
V: Necessary total tank capacity ( )
: Water expansion coefficient at average hot water
temperature
Vs: Total water amount in the system
P1: System pressure at tank setting position
(MPaabs.)
(Pipe inner pressure during pump operation
before heating device operates = water supply
pressure)
P2: Maximum pressure used during operation at tank
setting position (MPaabs.)
(= safety valve setting pressure)
* The absolute pressure value (abs.) is obtained by
adding the atmospheric pressure (0.1 MPa (1 bar))
to the gauge pressure.
▼ Tank selection method
Water temperature and expansion coefficient
Hot water
Expansion
temperature
rate
(°C)
0 0.0002
4 0.0000
5 0.0000
10 0.0003
15 0.0008
20 0.0017
25 0.0029
30 0.0043
35 0.0050
40 0.0078
45 0.0100
▼ Fig. 7-15
18
16
14
12
10
8
6
4
2
0
0 50 100
Water volume ( )
*Hot water temperature 55ºC
Install an external expansion vessel when the capacity
of the expansion vessel is insufficient.
Installation Manual
Hot water
Expansion
temperature
rate
(°C)
50 0.0121
55 0.0145
60 0.0171
65 0.0198
70 0.0229
75 0.0258
80 0.0292
85 0.0324
90 0.0961
95 0.0967
150 200 250 300