BCU 480 · Edition 06.07
52
Fault signalling
7 .6
The fault signalling contact opens, as soon as the mains volt-
age fails.
Protecting the pilot burner from overload
7 .7
To protect the unit against overload by frequent cycling, the
maximum number of start-ups per minute is limited for the
BCU. Excessive cycling triggers a fault message (blinking
53
). The max. number of start-ups per minute depends on the
safety time t
SA
and the ignition transformer used:
t
SA
[s]
Ignition transformer TZI
Max. start-ups/min.
3
5-15/100
6
5
5-15/100
6
10
5-15/100
3
3
7-25/20
3
5
7-25/20
2
10
7-25/20
1
3
7,5-12/100
6
5
7,5-12/100
4
10
7,5-12/100
2
3
7,5-20/33
4
5
7,5-20/33
3
10
7,5-20/33
2
Project planning information
