STEP 3 - Electrical Wiring
• To prevent electrical shock, turn off the electrical power before making electrical connections.
• This low water cut-off must be installed in series with all other limit and operating controls installed on the
boiler. After installation, check for proper operation of all of the limit and operating controls, before leaving
the site.
• Modification of the switch assembly before or after installation could cause damage to the boiler and/or
boiler system.
Failure to follow this warning could cause electrical shock, an explosion and/or a fire, which could result in
property damage, personal injury or death.
!
WARNING
Switch Operation
Boiler feed pump off,
burner on.
Boiler feed pump on,
burner on.
Boiler feed pump on,
burner off.
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2
5
6
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2
5
6
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2
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b.
Following the appropriate wiring
diagram, (refer to page 8)
based on your application
requirements, and using BX
armored cable or Thinwall elec-
trical metal tubing connector fit-
tings, make electrical connec-
tions to the junction box (LL).
Note:
Follow local codes and stan-
dards when selecting the types of
electrical fittings and conduit to
connect to control.
LL
Snap Switches
(Series 42S)
IMPORTANT:
There must be a
minimum space of 1/2” (13mm)
between connector fittings and
electrical live metal parts.
KK
a.
Using a flathead screwdriver, remove the
junction box cover (KK).
Summary of Contents for McDonnell & Miller 42S-N Series
Page 1: ...INSTRUCTION MANUAL MM 231G...
