Viessmann Vitocrossal 300 Service Manual page 92

Function Description
Internal Extensions EA1
Digital data inputs DE1 to DE3
The following functions can be connected alternatively:
H External heating program changeover for each heating
circuit
H External blocking
H External blocking with fault message input
H External demand with minimum boiler water
temperature
H Fault message input
H Brief operation of the DHW recirculation pump
External contacts must be dry.
Input function assignment
Select the input functions by means of codes in the
"General" group at the boiler control unit:
H DE1: Coding address 3A
H DE2: Coding address 3B
H DE3: Coding address 3C
Assigning the heating program changeover function to
the heating circuits
Select the heating program changeover function for the
respective heating circuit via coding address D8 in the
"Heating circuit" group at the boiler control unit:
H Changeover via input DE1: Code D8:1
H Changeover via input DE2: Code D8:2
H Changeover via input DE3: Code D8:3
The effect of the heating program changeover is selected
via coding address D5 in the "Heating circuit" group.
The duration of the changeover is set via coding address
F2 in the "Heating circuit" group.
92
(continued)
Effect of the external blocking function on the pumps
The effect on the respective heating circuit pump is
selected in coding address D6 in the "Heating circuit"
group.
The effect on a circulation pump for DHW tank heating is
selected in coding address 5E in the "DHW" group.
Effect of the external demand function on the pumps
The effect on the respective heating circuit pump is
selected in coding address D7 in the "Heating circuit"
group.
The effect on a circulation pump for DHW tank heating
is selected in coding address 5F in the "DHW" group.
DHW recirculation pump runtime for brief operation
The runtime is adjusted via coding address "3D" in the
"General" group.
Analog input 0 - 10V
The 0 - 10V hook-up provides an additional set boiler
water temperature:
0 - 1V taken as "no default for set boiler water
1V
10V
Ensure DC separation between the ground conductor and
the negative pole of the on-site voltage source.
Output aBJ
The following functions can be connected to output aBJ:
H DHW recirculation pump
or
H Fault output device (e.g. light, buzzer etc.)
Function assignment
Select the function of output aBJ via coding address "36"
in the "General" group at the boiler control unit.
Vitocrossal 300 CU3A 26 to 57 Service
temperature"
≙ set value 50°F (10°C)
≙ set value 212°F (100°C)