Testing Gas And Water Connections For Leaks - Bosch Greenstar Series Installation And Service Instructions For Contractors

Installations  Fig. 35 Stainless steel wall termination
2" PIPE Maximum straight vent pipe length
Number of 90° elbows
used
1 76 ft (23.1 m)
2 71 ft (21.6 m)
3 66 ft (20.1 m)
4 61 ft (18.6 m)
5 56 ft (17.1 m)
6 51 ft (15.6 m)
Table 18 Vent and combustion air pipe lengths with 2" diameter and the
stainless steel wall termination
Installations  Fig. 38 Concentric termination
2" PIPE Maximum straight vent pipe length
Number of 90° elbows
used
1 66 ft (20.1 m)
2 61 ft (18.6 m)
3 56 ft (17.1 m)
4 51 ft (15.6 m)
5 46 ft (14.1 m)
6 41 ft (12.5 m)
Table 19 Vent and combustion air pipe lengths with 2" diameter and the
concentric termination
Ø 3" / Ø 5" (Ø 80/125 mm) Concentric venting system
The maximum total concentric pipe length ( tab. 20) depends on the
installation situation, the appliance type and the number of elbows used.
Installations  Fig. 41
Ø 3" / Ø 5" (Ø 80/125 mm) Maximum straight vent pipe length
CONCENTRIC PIPE
Number of 90° elbows used
1
2
3
4
5
6
Table 20 Pipe lengths with Ø 3" / Ø 5" (Ø 80/125 mm) diameter and
termination
Greenstar – 6721822579 (2021/01)
allowed for Ø 2" pipe
ZBR 21-3A ZBR 35-3A
ZBR 28-3A ZWB 35-3A
ZWB 28-3A ZBR 42-3A
ZWB 42-3A
60 ft (18.3 m)
52 ft (15.9 m)
43 ft (13.1 m)
35 ft (10.7 m)
27 ft (8.2 m)
18 ft (5.5 m)
allowed for Ø 2" pipe
ZBR 21-3A ZBR 35-3A
ZBR 28-3A ZWB 35-3A
ZWB 28-3A ZBR 42-3A
ZWB 42-3A
47 ft (14.3 m)
38 ft (11.6 m)
30 ft (9.1 m)
22 ft (6.7 m)
13 ft (4.0 m)
5 ft (1.5 m)
allowed for Ø 3" / Ø 5" (Ø 80/125
mm) concentric pipe
ZBR 21-3A ZBR 35-3A
ZBR 28-3A ZWB 35-3A
ZWB 28-3A ZBR 42-3A
ZWB 42-3A
50 ft (15.2 m) 44 ft (13.4 m)
44 ft (13.4 m) 38 ft (11.6 m)
38 ft (11.6 m) 32 ft (9.8 m)
32 ft (9.8 m) 26 ft (7.9 m)
26 ft (7.9 m) 20 ft (6.1 m)
20 ft (6.1 m) 14 ft (4.3 m)
Fitting
45° elbow
90° elbow
Table 21 Concentric pipe friction loss equivalent for fittings
Example:
• Model: ZBR 28-3A
• 90° elbows used: 2
• 45° elbows used: 2
Maximum straight vent pipe allowed: 38ft (11.6 m)
6.9

Testing gas and water connections for leaks

NOTICE
Pressure, control and safety equipment may be damaged by
excessive pressure.
▶ When you carry out a leakage test, make sure that no pressure,
control or safety equipment is installed that cannot be isolated from
the test pressure.
▶ The boiler and its dedicated shutoff valve must be disconnected from
the gas supply piping system during any pressure testing of that
system at test pressures in excess of 14" W.C. (35 mbar).
Water connections
▶ Open the heating supply and return valves and fill the heating system.
▶ Check all connections for leakage (test pressure: Max. 30 psi (2.07
bar) on the pressure gauge).
Gas line
▶ Close the gas shutoff valve to protect the gas valve from damage.
▶ Check all connections for leakage (test pressure: Max. 60" W.C.
(150 mbar)).
▶ Release pressure.
Notes on installation and operation
Equivalent
ft m
3 0.91
6 1.82
43