
PFA, BGT · Edition 03.11l
6
Application
1 .1 .3 PFA 710 with PFU 780, stage-controlled main
burner with alternating pilot burner
VR..L
VAG
t
1
2
ϑ
1
ϑ
2
UV
02–04
02–04 06–08
06–08
VBY
TZI
2
1
DI
L1, N, PE
P
BUS
PFU 780
PFU 780
PFU 780
PFU 780
PFU 780
PFU 780
PFU 780
PFU 780
PF
A 710
BUS
SPS
Control: main burner ON/OFF
The main burner can be started with reduced capac-
ity after the operating signal from the pilot burner has
been detected. The pilot burner is switched off auto-
matically after the main burner has started up. When
the main burner is switched off, the pilot burner auto-
matically switches on again.
A UV sensor monitors the flame signal from pilot and
main burners. UV sensor UVD 1 is used for continuous
operation, UV sensor UVS for intermittent operation.
1 .1 .4 PFA 710 with PFU 780, stage-controlled main
burner with permanent pilot burner
VR..R
VAG
VBY
TZI
t
1
2
04
02–04 06–08
06–08 04
2
1
ϑ
1
ϑ
2
DI
L1, N, PE
P
BUS
PFU 780
PFU 780
PFU 780
PFU 780
PFU 780
PFU 780
PFU 780
PFU 780
PF
A 710
BUS
SPS
Control: main burner ON/OFF
The main burner can be started with reduced capac-
ity after the operating signal from the pilot burner has
been detected. Pilot and main burners can be operated
simultaneously. Both are ionization-controlled inde-
pendently.
Control: main burner High/Low
The main burner starts at low-fire rate. When the oper-
ating state is reached, the PFU 780L advises the con-
trol unit. The PLC can now pulse the air valve in order to
control the capacity of the main burner.