Bosch Installation Manual

Notes on installation and operation
31
Greenstar – 6721822579 (2021/01)
6.2 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)
Fig. 13 Operating capacity of the expansion vessel in °F and gallons
Fig. 14 Operating capacity of the expansion vessel in °C and liters
Key to Fig. 13 and Fig. 14:
[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
V
Supply temperature in °F ( °C)
V
A
System capacity in gallons (liters)
A Within operating capacity of the expansion vessel (left of the
relevant curve)
B Additional expansion vessel required (right of the relevant curve)
▶ If results are borderline: Determine precise vessel sizes.
▶ If the results are to the right of the curve: Install additional expansion
vessel.
6.3 Selecting an external expansion vessel (ZBR...-3A)
▶ Determine the size of the expansion vessel in compliance with local
laws and regulations.
Fig. 15 Example of installation of an external expansion vessel
6.4 Selecting the installation location
Installation location requirements
Observe the current national and local codes and regulations.
▶ Observe country-specific requirements.
▶ Observe installation instructions of the venting system accessories
and their clearances.
Combustion air
To avoid corrosion, keep the supply of combustion air free of corrosive
substances; contained in solvents, paints, adhesives, propellants and
domestic cleaning agents.
Table 13 Corrosive materials
Surface temperature
The max. surface temperature of this appliance is below 185 °F (85 °C).
According to ANSI/Z223.1/NFPA54 (National fuel gas code) and CAN/
CGA B 149.1 (Natural Gas and Propane installation code), the appliance
is approved for zero clearance to combustibles. For servicing a clearance
of 4" (102 mm) is recommended.
200
80
100
120
140
160
180
0 20 40 80 100
120
60
t
V
/°F
V
A
/gal
6720641933-13.1O
A
B
I
III
II
90
30
40
50
60
70
80
0
75 150
300
375
450
225
t
V
/°C
V
A
/l
6720641933-27.1O
A
B
I
III
II
Industrial sources
Chemical cleaning Trichloroethylene, tetrachloroethylene, fluorinated
hydrocarbons
Degreasing bath Perchloroethylene, trichloroethylene,
methylchloroform
Printing shops Trichloroethylene
Hair salons Aerosol propellants, hydrocarbons containing fluorine
and chlorine (difluorodichloromethane)
Household sources
Cleaning and
degreasing agents
Perchloroethylene, methylchloroform,
trichloroethylene, methylene chloride, carbon
tetrachloride, hydrochloric acid
Workshop
Solvents and thinners Various chlorinated hydrocarbons
Aerosols Chlorofluorinated hydrocarbons
(difluorodichloromethane)
6 720 641 933-20.3O