BCU 480 · Edition 03.16l
61
Project planning information
6 .11 Fault signalling
The fault signalling contact opens, as soon as the mains
voltage fails.
6 .12 Protecting the pilot burner from overload
To protect the unit against overload by too frequent cy-
cling of the pilot burner, the number of start-ups within
one minute is limited for the BCU. Excessive cycling of
the pilot burner triggers a fault message (blinking
53
). The max. number of start-ups per minute depends on
the safety time t
SA1
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
6 .13 Installation
Recommended installation position: vertical (cable
glands pointing downwards).
When installing, ensure that there is sufficient space to
open the BCU.
From inside
Open BCU and screw on with four screws (Ø 4 mm, min.
length 15 mm).
From outside
163 mm
185 mm
7.28"
6.42"
Screw on the closed unit to the rear with 4 self-tapping
screws (enclosed).
Otherwise, mount with external securing bars or the
fastening set, see page 71 (Accessories).