Technical data

Boiler Connections
28
Installation Examples (continued)
Waterside flow (primary circuit)
The Vitodens 200-W, WB2B is designed for closed loop, forced circulation hot water heating systems only.
Pressure drop (primary circuit) for
Vitodens 200-W, WB2B 19, 26, 35
For sizing an on-site circulation system.
Max. flow rate 6.2 USGPM/1400 L/h
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 above),
falls below the minimum flow rate or if
system flow rate is unknown,
Viessmann strongly recommends the
installation of a low-loss header.
Table 3. Typical System Flow Rates
Model WB2B 19 26 35
∆
∆∆
∆ t for NG/LPG
Output (NG/LPG) MBH 61 85 114
20ºF rise (GPM) 6.1 8.5 11.4
25ºF rise (GPM) 4.9 6.8 9.1
30ºF rise (GPM) 4.1 5.7 7.6
35ºF rise (GPM) 3.5 4.9 6.5
40ºF rise (GPM) 3.1 4.3 5.7
Boilers max. flow rate 6.2 GPM/
1400 L/h
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.
Viessmann therefore strongly
recommends and prefers the use of a
low-loss header over closely spaced
tees. Refer to the Technical Data
manual for low-loss header information.
5369 297 v1.6
Fig. 22
0 500 1000 1500
0
1
2
3
4
5
6
0
3.3
6.6
9.8
13.1
16.4
19.7
ft.
2000 L/h
7
8
23
26
Supply head pressure (ft. water)
0 2.2 4.4 6.6 8.8 GPM
m