General wiring requirements:
Electric shock hazard. Can cause
severe personal injury or death if
power source, including service switch on boiler, is
not disconnected before installing or servicing.
• Installations must follow these codes:
— National Electrical Code, ANSI/NFPA 70,
latest edition and any additional national,
state or local codes.
— In Canada, CSA C22.1 Canadian Electrical
Code Part 1 and any local codes.
• Wiring must be N.E.C. Class 1. If original wire
as supplied with boiler must be replaced, type
105°C wire or equivalent must be used. Supply
wiring to boiler and additional control wiring
must be 14 ga. or heavier.
• Provide electrical ground at boiler as required
by codes.
Thermostat wiring:
• Install thermostat on inside wall away from
influences of drafts, hot or cold water pipes,
lighting fixtures, television, sun rays or fireplaces.
• Follow instructions with thermostat. If it has a
heat anticipator, set heat anticipator in
thermostat to match power requirements of
equipment connected to it. Boiler wiring
diagrams give setting for standard equipment.
Junction box (furnished):
• Junction box houses electrical connections for
all boiler components.
• “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.
• On “A” boilers, mount the plug (provided in
water trim carton) on the burner housing as
shown in FIGURE 15. 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.
Boiler Wiring for Forced Hot Water
FIGURE 15
Tankless Heater Control
Wiring Harness
(Furnished as part of tankless
heater kit as additional
equipment from W-M)
Circulator Wiring Harness
(Not Furnished on A Boilers)
Burner Wiring Harness
Burner Disconnect Plug
Limit Wiring Harness
18
Connect Wiring