Figure 20
Boiler wiring for probe-type LWCO — component
locations for wiring diagram, Figure 19, page 28
Connect wiring
(Probe-type LWCO)
(continued)
1
3
4
5
2
1
Pressure control wiring harness
2
Tankless heater control wiring
3
Burner disconnect plug
4
Burner wiring harness
5
Low water cutoff wiring harness (not furnished
on “A” boilers)
Blocked vent safety switch (BVSS),
when required
In Canada, a blocked vent shutoff switch kit
must be installed (see parts list page 38). See Fig-
ure 15, page 25.
The BVSS wiring diagram in Figure 21 shows
boiler wiring only up to the burner disconnect.
For additional information, refer to manufacturer’s
instructions.
1. Locate and remove boiler junction box cover.
2. Locate wire nut with two black wires (if more than one exists,
pick the one with black wire going to the burner harness).
Clip the wire nut.
3. Strip 1/2" from the end of both the black wires.
4. Clip the quick connects from the blue wires coming from the
BVSS Harness and strip 1/2" from the ends.
5. Using two wire nuts from the kit, connect the blue wires in
series with the two black wires (see Figure 21).
6. Replace junction box cover.
7. Turn on power and verify safe operation of the appliance.
8. Restore boiler to normal operation.
120 vac field wiring
120 vac factory wiring
Figure 21
BVSS wiring diagram (probe-type LWCO)
Part number 550-141-829/1211
29
GOLD
SGO
OIL-FIRED NATURAL DRAFT STEAM BOILER — SERIES 3 —
Boiler Manual
SERVICE TECHNICIAN ONLY — read and follow completely.
