Comparing The Size Of The Integrated Expansion Vessel - Bosch ZBR16-3A Installation And Service Instructions Manual

5.2 Comparing the size of the integrated
expansion vessel
The following diagrams allow verifying that the integrated
expansion vessel has sufficient capacity for the intended
application, or if an additional expansion vessel is needed
(not for radiant floor heating).
The following standard conditions were used:
• Precharge volume 20% of the rated volume in the
expansion vessel
• Differential to the safety valve of 7.25 psi (0.5 bar)
• Precharge pressure of the expansion vessel equal to the
static system height above the boiler
• Maximum operating pressure: 30 psi (2.07 bar)
200
I
180
160
140
120
III
100
II
A
80
0 20 40
Fig. 9 Operating capacity of the expansion vessel in °F and
gallons
Copyright (optional information)
B
60 80 100 120
V /gal
A
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90
I
80
70
60
50
III
40
II
A
30
0 75 150
Fig. 10 Operating capacity of the expansion vessel in °C
and liters
Key to Fig. 9 and Fig. 10:
I Precharge pressure 7.25 psi (0.5 bar) (default setting)
II Precharge pressure 10.9 psi (0.75 bar)
III Precharge pressure 14.5 psi (1.0 bar)
t Supply temperature in °F ( °C)
V
V System capacity in gallons (liters)
A
A Within operating capacity of the expansion vessel (left of the
relevant curve)
B Additional expansion vessel required (right of the relevant
curve)
B If results are borderline: Determine precise vessel sizes.
B If the results are to the right of the curve: Install
additional expansion vessel.
Installation | 37
B
450
225 300 375
V /l
A
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