Honeywell Krom Schroder BCU 580 Technical Information page 66

Parameters
Parameter 78 = 2: burner 1 and burner 2. Three valves
(V1, V2 and V4) are included for a modulating burner
with a pilot burner. These are connected to the valve
outputs (terminals 13, 14 and 57). Valves V1 and V4
open to start the pilot burner. Gas valve V2 releases the
gas supply to the main burner.
13 14 57
BCU 570
H1 02 03 06 07
µC
t t t
SA1 FS1 SA2
Parameter 78 = 3: burner 1 and burner 2 with pilot gas.
In this application, the burner has an additional pilot
gas valve V3. The valves are connected to the valve
outputs (terminals 13, 14, 15 and 57). Valves V1 and
V4 open to start the pilot burner. The burner is started
with a limited ignition capacity using gas valve V3. After
BCU 580 · Edition 11.15l
V1
V2
V4
H8 08
9
13
55
54
14
53
15
56
57
5
8
17-18
t t
FS2 RF
the elapse of the safety time t
valve V2 opens (terminal 14). Pilot gas valve V3 is closed
again after the elapse of the flame proving period t
(program step 07).
For this application, it must be ensured that the flame
proving period (P97) is set to a value ≥ 2 s.
BCU 570..C1F1
1
H1 02
2
3
4
1
2
58
t
t
SA1
▼
(program step 06),
SA2
V1
V2
13 14 15 57
03 06 07 H8 08
µC
52
55
54
53
56
47 48
t t t t
FS1 SA2 FS2 RF
FS2
V3
V4
9
13
1
14
2
15
3
57
4
5
1
8
2
17-18
t
66