User Guide

52
P3‐6
S7910BDisplay
R7910BBoilerControl
+V
J3‐A
J3‐A
‐V
J3‐B
J3‐B
MB1
MB2
ReturnSensor
SupplySensor
Spark
J1‐2
J9‐1
J9‐2
J9‐3
J9‐4
J9‐5
J9‐6
WiringLegend
R7910BBoilerControl
AT140B
DHWPump
BoilerPump
SystemPump
Gnd
J8‐3
J8‐2
J6‐3
J4‐10
J7‐7
J4‐12
J8‐1
J5‐1
J6‐2
J5‐2

GasValve
Sump
Press.Sw.
Ext.
Limit
T1‐5
P2‐4
CHT’stat
DHWT’stat
T1‐6
T1‐3
T1‐4
T1‐1 T1‐2
Flow
Sw.
J3‐ECOM1
J3‐ECOM2
J3‐ECOM3
Ignitor
Flame
Rod
FactoryWireHarness
Fieldwiring
Connector
Screw
Terminal
120VAC/60Hz/1Ph
L3‐1
J4‐4
J4‐2
J4‐6
J4‐3
J4‐5
J4‐7
CombustionFan
(120VConn.)
1 3
2
J8‐6
J8‐10
J8‐4
J8‐9
J8‐8
J8‐11
J8‐5
J10‐7
J10‐8
Outdoor
Temp
J6‐7
J6‐8
1
2
3
FlueGasSensor
1(DC+)
2(Tach.)
4(PWM)
5(DC‐)
J2‐3(FanPWM)
J2‐4(DC‐)
J2‐1(Tach.)
J2‐2(DC+)
CombustionFan
(DCConn.)
T1‐8
T1‐7
Internal,non
replaceable2amp
J6‐1
L3‐2
L2‐1 L2‐3
Thermal
Fuse
Groundscrewin
boilerJ‐box
“AirProving
Switch”
L
WireNut
N
P3‐7
P3‐8
P1‐1
P1‐2
P1‐4
P1‐3
P1‐5
P3‐5
P3‐2
P3‐4
P2‐1
P2‐3
P2‐2
P2‐6
P3‐9
P3‐1
P3‐12
P2‐5
P3‐10
P3‐3
P3‐11
P4‐5
P4‐4
P4‐1
P4‐11
P4‐10
P4‐2
P4‐7
P4‐8
P4‐12
P4‐9
P4‐3
P4‐6
Condensate
Trap
¼”Q.C.
PCBTrace/Components
Groundscrew
onboilerframe
FIGURE 10.5: INTERNAL LADDER DIAGRAM