Viessmann Vitodens 100-W Technical Data Manual page 16

Installation Examples
System Layout 2
Vitodens 100-W, WB1B 10-26, 10-35 with...
– DHW storage tank
– low-loss header
– one heating circuit
AV
PRV
Y
Fig. 14
IMPORTANT
Primary pump must pump into
the boiler (as illustrated).
Please note!
The use of a low-loss header is
recommended if the water flow rate is
less than 1.7 GPM / 400 ltr/h or more
than 6.2 GPM / 1400 ltr/h.
The low-loss header is available as
accessory part.
IMPORTANT
DHW supply and return piping between boiler DHW connections and the Viessmann DHW tank connections, shall be a minimum of
1" nominal pipe diameter (irrespective of the ¾" DHW connection outlet sizes provided on the boiler and the DHW tank). This
ensures that the head of the pump is fully utilized to overcome the resistance of the DHW heat exchanger coil and to provide
sufficient water flow to the boiler heat exchanger. In non-Viessmann DHW tank applications, perform, in addition to the above,
accurate calculations for DHW tank coil pressure drop versus boiler pump head to ensure sufficient water flow to the boiler heat
exchanger. Failure to heed the above instructions may cause boiler short-cycling and inadequate DHW supply.
16
TPV
Y
Maximum Flow Rates
Model WB1B 10-26
∆ ∆ ∆ ∆
t
83,000 108,000
Output
Btu/h
30ºF rise (GPM) 5.5
35ºF rise (GPM) 4.7
40ºF rise (GPM) 4.2
AV Air vent
PRV Pressure relief valve
TPV Temperature and pressure relief
valve
Vitodens 100-W gas-fired
condensing boiler
External boiler/DHW controller (field
supplied)
Heating circuit
Heating circuit pump (field supplied)
DHW storage tank
DHW tank temperature aquastat or
sensor
DHW circulating pump (field
supplied)
Low-loss header
Expansion tank
Primary pump (boiler circuit, field
supplied) with low-loss header only
10-35
----
6.2
5.4