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Chapter 4. Explanation of Operation
 z Q890A100 base unit for RA890-AUR890 replacement
 Non-recycling gas-fired combustion
Terminal layout 
of connector
 for front wiring
*1  Use the external controller for either the power 
  or for low voltage. If the line voltage controller 
  is used to start burner controller operation, 
  connect terminal 17 to terminal 20.
:  Terminal numbers of AUR890/BC-R05
F
Low voltage 
temp. controller 
*1
Flame voltage
circuit
10A
Terminal numbers of Q890A100 base unit (for RA890 replacement)
AUR890/BC-R05A100
5
L1
Circuit 
breaker
L2(N)
Line voltage 
temp. controller 
*1
Prepurge completion signal
1
Burner on-off circuit Limit / interlock circuit
Blower operation circuit / prepurge circuit
AC input 
circuit
6
8
46
37
12
23
10
25
RESET
switch
DISP
switch
FLAME
ALARM
Display
Combustion
safety
control
circuit
Input
circuit
(24 V DC)
24 V DC
17
T
+
20
T
14
F
G
FV+ FV
-
Alarm 
output COM
15
G
Flame 
detector
Flame
detection
circuit
K1
Power 
supply circuit
K4
K5
K3
K2
K6
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:  Terminal numbers of Q890A100 base unit 
   (for RA890 replacement)
:  Terminal numbers of the front connector
Alarm
COM
11
Alarm 
output NO
NO
12
Alarm 
output NC
NC
Pilot valve 1
Main valve 1
Pilot valve 2
TM
1
TM1
TM1
103X
Ignition transformer
Main valve 2
103
X
TM1