A.O. Smith 400 - 2100 Installation & Operation Manual page 69

11
Ladder diagram
WITCHES ARE SHOWN WITHOUT
WATER OR ELECTRICITY )
NIT. AS SUCH, SWITCH STATES
THOSE SHOWN ON DIAGRAM
WHETHER UTILITIES ARE
T CONDITION IS PRESENT . SEE
M FOR ADDITIONAL NOTES .
HiGas
LoGas
O/BK
FACTORY
2
O/BK
FLOW
1
O
SWITCH
O
C
1 2
LoGas
2
1
O
1 2
O O/BK
DANGER
!
TO PREVENT ELECTRICAL SHOCK
HIS HEATER MAY BE CONNECTED TO MORE THAN ONE BRANCH CIRCUIT . M ORE THAN ONE
SCONNECT SW ITCH MAY BE REQUIRED TO DE-ENERGIZE THE EQUIPM ENT FOR SERVICING.
(continued)
PROVING
LOUVER
SWITCH
PROVING
W
LM
TO POWER
LOUVER
SOURCE
BK CONTACTS
LOUVER TERMINAL BLOCK
AUX.
HI-LIMIT
NO
BURNER
GROUND
C
NC
NO
MANUAL
IGNITER
RESET
HI-LIMIT
O
1 2
1 2
O
O
C
NC
O
AIR PRESS
SWITCH
PR/BK
6 6 PR/BK
ARMING RELAY
PR
5 5
PR
BL BL BL
4 4
3 3
R R
RUN
T
O 2 2 O
Y 1 1 Y
T/W
T
W
BR
LV
BR
BK
BK
-
+
F1
5 S1
GY
F2
4
GY
LINE
TRIAL 3
NEU
2 W
GY
GY 1 S2/FS
IGNITION
MODULE
11
PURGE
TH
O 10
9 PI
RESET
T
8 24COM
7
RESET
6 24VAC
MV
5
T/W PS
4
3
ALARM
2
FF
BL 1
PR/
BK
Y Y
ARM
NO
TD Y
BL/W
TIME
C
NC
DELAY
Y
RUN
PR
C
PR
NC
Y
C
NO
P
P
Installation & Operation Manual
1 2 3 4
4 3 2 1
T T/W
BK/
W (NOT ON 500)
LOW
R
BK/ BK/
W W BK
- HIGH
W
STATUS
+
BK
HIGH FIRE VALVE (S)
R
R/BK
LOW FIRE VALVE(S)
R R
R
R
R/BK H/L
HIGH/LOW FIRE RELAY
BL
1 1
2 2 PR PR
SILENCING
ALARM
SWITCH
BELL
+
ALARM
CONTACTS
+
+
RUN-TIME
CONTACTS
+
LBL20332 REV B
W
W
W
BLOWER
W
G
W
HIGH
Y
Y
Y
LOW
Y
Y
69