Viessmann VITOCROSSAL 300 Technical Data Manual page 17

Vitocrossal 300 CU3A 26 to 57 Technical Data
Accessories for Vitocrossal 300 CU3A
Low-Loss Header (continued)
Principle of Operation
Legend
T1 Boiler supply temperature
T2 Boiler return temperature
T3 System supply temperature
T4 System return temperature
Vprimary Boiler circuit flow rate
Vsecondary Heating circuit flow rate
Vbypass Bypass flow rate
Qprimary Heat supplied by boiler
Qsecondary Heat consumed by system
IMPORTANT
When installing a low-loss header, the system mixed
supply temperature (T3) must be calculated as follows:
Vprimary < Vsecondary
T1 > T3
T2 = T4
Qprimary = Qsecondary
T1 167° F (75° C)
Vsecondary=Vprimary+Vbypass
Model No.
Type 80/60
Type 120/80
Type 160/80 *1
Type 200/120 *1
*1 Floor-mounted version (typically used for
multiple-boiler installations).
Accessories
Max. system flow rate
17.6 USGPM (4 m 3 /h)
35.2 USGPM (8 m 3 /h)
44 USGPM (10 m 3 /h)
80 USGPM (18 m 3 /h)
17