Connect wiring, Boiler manual – Weil-McLain 550-141-826/1201 User Manual
Page 23
SERVICE TECHNICIAN ONLY — read and follow completely.
High temperature limit
• To comply with ASME, UL 726 or Canadian requirements, an additional
high temperature limit is needed.
• Install the secondary control in the supply piping between boiler and
isolation valve.
• Set the control to a minimum of 20˚F above the set point of the com-
bination control.
• The maximum allowable set point is 220˚F.
• Wire the control as shown on page 24.
Limit control
wiring harness
Circulator
wiring
harness
(not
furnished
on “A”
boilers)
Service
switch
on
boiler
Burner
wiring
harness
Burner
disconnect plug
Figure 16
Boiler wiring for forced hot water
Junction box (furnished)
• Junction box houses electrical connections for all
boiler components.
• “P” boilers have harnesses furnished.
• “A” boilers are furnished with burner and limit
harnesses.
• All field-provided high voltage wiring must be
sheathed in flexible metal conduit.
• Connect incoming line voltage “HOT” wire to
service switch, and neutral wire to white wire.
Field-install equipment ground wire to green wire
with wire nut.
• Service switch (15 amp) is provided with boiler. “A”
boilers — install switch as shown.
• Some local codes may require an emergency shut-
off switch installed at a location away from boiler.
Follow local codes.
Burner wiring
• Burner harness incorporates a disconnect plug,
providing a convenient way to disconnect wiring
when burner mounting door is opened.
• All “P” boilers have a power disconnect plug in-
stalled on burner.
• On “A” boilers, mount the plug (provided in water
trim carton) on the burner housing as shown in
Figure 16. For Carlin burners, screw burner plug
into threaded conduit coupling, then mount this
assembly to the burner housing using the chase
nipple. Route wires through housing and make
connections in burner junction box as shown in
boiler wiring diagram.
Connect wiring
(continued)
Part number 550-141-826/1211
23
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OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 —
Boiler Manual