Viessmann Vitocrossal 300 Series Technical Data Manual page 22

Installation Examples
System Layout 3
Vitocrossal 300 CU3A with...
- DHW storage tank
- one direct-connected heating circuit
- two heating circuit with a mixing valve
Legend
Vitocrossal 300 CU3A boiler with
A
Vitotronic 200, KW6B outdoor reset control
Outdoor temperature sensor !
B
Vitotrol remote (optional)
C
D Under floor heating circuit
Radiator heating circuit
E
F Heating circuit pump
G Mixing valve temperature sensor ?
Accessory kit for heating circuit with mixing valve
H
I Domestic hot water storage tank
DHW tank temperature sensor %
J
Expansion tank
K
L Temperature and pressure relief valve
Pressure relief valve
M
DHW recirculation pump
N
O Boiler pump
20
DHW circulating pump sA
P
* Function based on coding of address 53
22
*
28/20
Vitocrossal 300 CU3A 26 to 199 Technical Data
Installation of different heating circuits...
radiator heating circuit (high-temp. circuit)
■
under floor heating circuit with 3-way mixing valve
■
(low-temp. circuit)
■ DHW production
The 3-way mixing valve, built-in to achieve the low-
temperature level of the under floor heating circuit, is
controlled by an accessory kit for a heating circuit with
mixing valve.
IMPORTANT
System separation is required of underfloor heating
systems employing non-oxygen diffusion barrier tubing.
All components on the secondary side of the heat
exchanger must be made of corrosion-resistant materials.
IMPORTANT
Sizing of field-supplied pump P is critical for proper boiler
operation in this system layout. See page 8 for the supply
head pressure drop of the boiler. An undersized pump
may cause short-cycling and/or improper operation of the
boiler.