Viessmann VITODENS 100-W Technical Data Manual page 16

Installation Examples
System Layout 2
Vitodens 100-W, WB1A 8-24, 8-30 with...
– DHW storage tank
– low-loss header
– one heating circuit
PRV
Y
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.
See page 13 in this manual for details on
the low-loss header.
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
AV
Model No.
Vitodens 100-W,
WB1A 8-24
WB1A 8-30
TPV
Y
Max. flow rate
(GPM/ltr/h)
6.2/1400
6.2/1400
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