
Part number 550-100-305/0118
58
AquaBalance
TM
W
ALL
M
OUNT
GAS
-
FIRED
WATER
BOILER
—
Boiler Manual
25
Wiring diagram — WMB-155H Heating Only Ladder
Figure 74
WMB-
155H –– Heating Only Ladder Wiring Diagram
Legend
16
Fan
32
Central heating pump (not included)
44
Combination gas valve
72
Room thermostat (not included)
81
Ignition electrode
104(1) Fuse 3.15A
104(1) Fuse 630mA
114
Water pressure switch
130
DHW pump (not included)
138 Outdoor
sensor
143
DHW tank thermostat (not included)
186
Return temperature sensor
191
Exhaust temperature sensor
278
Double sensor (h safety)
279
Transformer 115-24 VAC
284
Relay SPST-Coil 24 VAC
370
LWCO (not included)
373
“OPENTHERM” communication (Not used)
cod. 3541M950
NOTES:
1. All wiring must be installed in
accordance with N.E.C. and
any other national state or local
requirements.
2. Room thermostat should be
a dry contact type and should
draw power from the control
board: should not be greater
than
24 VAC and 500 mA
.
3. Max. voltage and electric cur-
rent for the LWCO + CH PUMP
+ DHW PUMP should not be
greater than
120 VAC and 3
Amp
.
4. In case of questions during
installation please contact your
local Weil-McLain distributor.