– 11 –
Hydro Unit
Installation Manual
Checking water volume and initial pressure
of expansion vessel for Heating
The expansion vessel of the Hydro Unit has a capacity
of 10 liters.
The initial pressure of the expansion vessel is
0.05 MPa (0.5 bar).
The pressure of the safety valve is 0.25 MPa (2.5 bar).
Verify whether the capacity of the expansion vessel is
sufficient using the following expression. If the volume
is insufficient, add the capacity locally.
Expression for expansion vessel selection
V: Necessary total tank capacity ( )
: Water expansion coefficient at each hot water
temperature
Vs: Total water amount in the system
P1: System pressure at tank setting position
(MPaabs.)
= water supply pressure = 0.15 (MPaabs.)
(recommended value)
P2: Maximum pressure used during operation at tank
setting position (MPaabs.)
= safety valve setting pressure = 0.35 (MPaabs.)
* The absolute pressure value (abs.) is obtained by
adding the atmospheric pressure (0.1 MPa (1 bar))
to the gauge pressure.
▼
Tank selection method
▼
Fig.7-09
Install an external expansion vessel when the capacity
of the expansion vessel is insufficient.
Water temperature and expansion coefficient
Hot water
temperature
(°C)
Expansion
rate
Hot water
temperature
(°C)
Expansion
rate
0
0.0002
50
0.0121
4
0.0000
55
0.0145
5
0.0000
60
0.0171
10
0.0003
65
0.0198
15
0.0008
70
0.0229
20
0.0017
75
0.0258
25
0.0029
80
0.0292
30
0.0043
85
0.0324
35
0.0050
90
0.0361
40
0.0078
45
0.0100
0
2
4
6
8
10
12
0
50
100
150
250
200
300
*In case the maximum hot water temperature is 65ºC
V: Nec
ess
ary
total
tank
capac
ity
()
Vs: Total water amount in the system ( )
Pump operation/configuration
0
1
2
3
4
5
6
7
8
9
10
0
5
10
15
20
25
30
35
40
Hydraulic heat exchanger (6 kW) QH characteristics
Minimum flow rate
He
ad
[
m
]
Out of range
Hydro unit (AIO ZONE1)
Q-H characteristics
Pump duty
100%
80%
Flow rate [L/min]
▼
Fig.7-10
60%
0
1
2
3
4
5
6
7
8
9
10
0
5
10
15
20
25
30
35
40
Hydraulic heat exchanger (11 kW) QH characteristics
Minimum flow rate
He
ad
[m
]
Out of range
Hydro unit (AIO ZONE1)
Q-H characteristics
Pump duty
100%
80%
Flow rate [L/min]
▼
Fig.7-11
60%
0
1
2
3
4
5
6
7
8
9
10
0
5
10
15
20
25
30
35
40
He
ad
[
m
]
Flow rate [L/min]
Hydro unit (AIO ZONE2)
Q-H characteristics
Pump duty
100%
21-EN
22-EN
Summary of Contents for HWT-1101F21MM3W-E
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