Siemens SQN72 Series Manual page 19

Key
A
I/II
III/IV/V
AL
BV1
BV2
BV3
EK2
ION
F
FS
GP
HS
KL
L
LK
LKP
LP
LR
M
M
M1
M2
N
NL
OH
OW
QRB
R
RV
SA
Si
SB
STx
tx / Tx
TSA
R
Z
CLOSED


Program sequence – Diagrams
A Burner ON
A–B Burner startup
B–C Burner operation / load control operation, modulating or 2-stage
C Burner OFF
C–D Postpurge time
D End of program sequence, burner control ready for restart
Control signals delivered by burner control
Required input signals
Permissible input signals
Smart Infrastructure
Designation for internal circuit.
Appears in the second position after the period in the type reference
End switches
Auxiliary switches
Remote lockout display (alarm)
Fuel valve stage 1
Fuel valve stage 2
Fuel valve stage 3
External remote lockout reset button
Ionization probe
Internal fuse, not replaceable
Flame signal
Gas pressure switch
Main switch
Low-fire
Phase
Air damper
Air damper position
Air pressure switch
Load controller
Burner motor or fan motor
Actuator synchronous motor
Without postpurging
With postpurging
Neutral conductor
High-fire
Oil preheater
Oil preheater release contact
Photoresistive detector
Control thermostat or pressurestat
Relay
Control valve
Actuator
External primary fuse, as specified in the data sheet of the relevant burner control
Safety limiter
Stage
Program times (refer to the data sheet of the relevant burner control)
Safety time
Resistor
Ignition transformer
Damper closed
Direction of rotation OPEN
Direction of rotation CLOSED
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CC1N7802en
8/11/2021