Viessmann WB1A Series Installation And Service Instructions Manual page 27

Installation Examples
26 8
23 7
6
19.7
16.4 5
13.1
4
9.8 3
6.6 2
3.3 1
0 0
0 1.1 2.2
0 250 500
Flow rate
Pressure drop for model WB1A 8-24, 8-30
Typical System Flow Rates
Model WB1A 8-24
∆ ∆ ∆ ∆
t for NG
72 000
Output (NG)
Btu/h
20 ºF rise (GPM) 7.2
25 ºF rise (GPM) 5.8
30 ºF rise (GPM) 4.8
35 ºF rise (GPM) 4.1
40 ºF rise (GPM) 3.6
Use standard friction loss method for pipe sizing.
Observe boiler maximum and minimum flow rate limitations. If system flow rate exceeds
boiler maximum flow rate (as stated on page 68) or if system flow rate is unknown, Viessmann strongly
recommends the installation of a low-loss header. See page 36 for low-loss header information or refer to the Vitodens
Venting System Installation Instructions.
Important!
The following examples depict possible piping layouts of the Vitodens 100-W boiler equipped with Viessmann System
Technology.
Please note that the examples below are simplified conceptual drawings only!
Piping and necessary componentry must be field verified.
A low water cut-off (LWCO) must be installed where required by local codes.
Proper installation and functionality in the field is the responsibility of the heating contractor.
All manuals and user guides at all-guides.com
(continued)
Pressure drop (primary circuit) of Vitodens 100-W
4.4 6.6 8.8
1000 1500 2000
8-30
90 000
9.0
7.2
6.0
5.1
4.5
11 13.2 15.4 GPM
2500 3000 3500 ltr/h
A low-loss header must be used when the system
flow rate exceeds the maximum (or minimum) flow
rate of the Vitodens 100-W boiler. An alternative
method may be used, such as primary secondary
piping using closely spaced tees.
A low-loss header offers additional benefits not
provided by a pair of closely spaced tees. Viess-
mann strongly recommends and prefers the use of
a low-loss header over closely spaced tees.
Boiler Connections
27