External Blocking; External Demand - Viessmann VITOCROSSAL Service Instructions Manual

Control functions
(cont.)
The duration of the operating program changeover can
be adjusted in coding address "F2":
Operating program changeover
No operating program changeover
Duration of the operating program changeover 1 to 12 h
The operating program changeover stays enabled for
as long as the contact remains closed, but at least as
long as the duration selected in coding address "F2".

External blocking

When the contact is closed, the burner is switched off.
The heating circuit pump and (if installed) circulation
pump for cylinder heating are switched according to
the set codes.
The external connection is switched via a floating con-
tact.
Connection options:
■ Plug
lH
■ EA1 extension (accessories)
Plug
lH
■ The function is selected via code "4b:2" in the "Gen-
eral"/1 group.
■ The effect on the circulation pump for cylinder heat-
ing is selected with code "5E" "DHW"/3.
The effect on the relevant heating circuit pump is
■
selected with code "d6" "Heating circuit".
External blocking
Input DE1
Input DE2
Input DE3
External blocking and fault message input
Input DE1
Input DE2
Input DE3

External demand

When the contact is closed, burner operation is load-
dependent. The boiler water is heated to the set value
selected in coding address "9b" in the "General"/1
group. The boiler water temperature is limited by this
set value and by the electronic maximum limit (coding
address "06" in the "Boiler"/2 group).
EA1 extension
The functions "External blocking" and "External block-
ing with fault message input" are implemented via the
EA1 extension. There are 3 inputs available at the EA1
extension (DE1 to DE3).
The function is selected via the following codes:
The external connection is switched via a floating con-
tact.
Connection options:
■ Plug
lH
■ EA1 extension (accessories)
Function description
Code
F2:0
F2:1 to
F2:12
Code
3A:3
3b:3
3C:3
Code
3A:4
3b:4
3C:4
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