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Building Technologies Division CC1N7451en
20.11.2017
Legend
a Changeover end switch for air damper’s OPEN position
AL Remote lockout warning device (alarm)
AR Load relay with contacts «ar...»
AS Unit fuse
BR Lockout relay with contacts «br...»
BV... Fuel valve
bv... Control contact for the CLOSED position of gas valves
d1 / d2 Contactor or relay
EK... Lockout reset button
FR Flame relay with contacts «fr...»
FS Flame signal
GP Gas pressure switch
H Main isolator
ION Ionization probe
L1 Fault signal lamp
L3 Operational readiness indication
LK Air damper
LP Air pressure switch
LR Load controller
M1 / M2 Fan or burner motor
m Changeover auxiliary switch for the air damper’s MIN position
NTC NTC resistor
QRA... UV detector
R Control thermostat or pressurestat
RV Modulating fuel valve
SA Air damper actuator
SB Safety limiter
Si External fuse
SM Synchronous motor of sequence switch
V Flame signal amplifier
v In the actuator: Changeover auxiliary switch for the position-dependent release of fuel
W Limit thermostat or pressure switch
Z Ignition transformer
z In the actuator: End switch for the air damper’s CLOSED position
ZBV Pilot gas valve
(1) Input for increasing the operating voltage for the QRA2 / QRA4 / QRA10 (detector test)
(2) Input for forced energizing of the flame relay during the functional test of the flame supervision circuit
(contact
XIV) and during safety time «TSA» (contact IV)
Valid for direct spark flame burners
Valid for interrupted pilot burners with a pilot burner, which is switched off following the ignition of the main
burner
A Start command given by the temperature controller
A-B Startup program
B Operating position of the burner
B-C Burner operation
C Controlled shutdown via control thermostat or pressurestat (R)
C-D Sequence switch runs to the end position following controlled shutdown via control thermostat or
pressurestat (R)
D-A End position of the burner control
corresponds to the start position
Control signals of the burner control
Permissible input signals
Required input signals:
If these signals are not present at the points in time marked by symbols or during the hatched periods of
time, the burner control interrupts the startup sequence or initiates lockout
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