Weil-McLain 550-141-826/1201 - Manual (Page 25)

SERVICE TECHNICIAN ONLY — read and follow completely.
Connect wiring — blocked vent shutoff switch option
Figure 18 Blocked vent shutoff switch installation Figure 19 BVSS wiring diagram
Blocked vent shutoff switch
In Canada, blocked vent shutoff switch kit
(see parts list page 34) must be installed.
See Figure 18. The wiring diagram in
Figure 19 shows boiler wiring only up
to the burner disconnect. For additional
information, refer to manufacturer’s
instructions.
Electric shock hazard. Turn off electrical
power supply at service entrance panel
before making any electrical connections
to avoid possible electric shock hazard.
Failure to do so can cause severe personal
injury or death.
After installing BVSS switch, proceed as follows:
1. Disconnect power.
120 vac
field wiring
Low voltage
field wiring
120 vac
factory wiring
Low voltage
factory wiring
2. Install Spill Switch (BVSS) Wiring Harness (P/N 591-391-942) as fol-
lows:
a. Remove cover from BVSS Box.
b. Install straight fitting end of the harness on the BVSS Box. Install
elbow (90º) end fitting on the Boiler Junction Box (see Figure 18).
c. Install both the fork ends to the screw terminals on the BVSS Switch
as per the wiring diagram, (see Figure 19).
d. Replace BVSS box cover.
e. Locate Combination Control, remove cover, and disconnect red
wire from “B1” terminal.
f. If red wire from Step “e” has uninsulated female end, replace it
with insulated female end as supplied in kit.
g. Connect female end of Spill Switch BVSS Harness (blue wire) to
“B1” terminal.
h. Connect male end of Spill Switch BVSS Harness to the red wire
removed in Step “e”.
i. Replace Combination Control Cover.
3. Turn on power and verify safe operation of the appliance.
4. Restore boiler to normal operation.
Part number 550-141-826/1211 25
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OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 —
Boiler Manual