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5790 733 - 07
Vitocrossal 300 CA3 Series 2.5 to 6.0 Installation/Service
Connection and Wiring Diagrams
Burner Control Unit Connection Diagram
CAUTION
Provide disconnect means and overload protection as
required.
WARNING
Disconnect power inside the boiler junction box, before
servicing boiler.
Legend
A
Burner control unit interface VUC 310/base
B
Flame sensor
aA
C
Vitotronic control unit
D
Ignition burner inlet damper
E
Ignition unit
gF
F
Gas valve V1
dG
G
Gas valve V2
dH
H
Fan motor with PWM control and feedback
a=Ö
A
I
Boiler temperature sensor 1
§
A
J
Boiler temperature sensor 2
§
B
K
AC-EMI suppression filter device
L
Secondary boiler water temperature sensor 1
aG
A
M
Secondary boiler water temperature sensor 2
aG
B
N
Inlet fan pressure switch
acA
(APS1)
O
Overfire pressure switch
acA
A
(APS2)
P
Inlet gas pressure switch
ayA
GDW1
Q
Gas pressure switch (outlet pressure at first valve
seat)
kJ
GDW2
R
Burner damper
S
Burner display and programming unit
F1/F2 Fuse
For CA3 3.5 to 6.0 boilers