Xylem MM 217K Series 150S and 157S Low Water Cut-Offs/Pump Controllers - Manual (Page 7)

STEP 4 - Electrical Wiring
• To prevent a fire, do not use this product to switch currents over 7.4A, 1/3 Hp at 120 VAC or 3.7A, 1/3 Hp at 240
VAC, unless a starter or relay is used in conjunction with it.
• 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
For all Models except 158S and 159S
For Model 158S
Boiler feed pump off,
burner on, alarm off.
Boiler feed pump on,
burner on, alarm off.
Boiler feed pump on,
burner off, alarm on.
1 2 4 5 6 1 2 4 5 6 1 2 4 5 6
Motorized valve closed,
burner on, alarm off.
Motorized valve open,
burner on, alarm off.
Motorized valve open,
burner off, alarm on.
4 5 6 1 2 3 4 5 1 2 3 4 5 1 2 3 6 6
For Model 159S
Pump #1 off,
pump #2 off.
Pump #1 on,
pump #2 off.
Pump #1 on,
pump #2 on.
1 2 5 6 1 2 5 6 1 2 5 6
K
a. Using a flathead screwdriver, remove the
junction box cover (K).
7