Product Overview

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• For residential, commercial and industrial low or high
pressure boiler applications
• For boilers of any steaming capacity
• Monel bellows provides corrosion resistance
• Float chamber with integral water column provided
•`Snap action for high temperature service
– 1 Single pole, single throw switch for pump control
– 1 Single pole, double throw switch for low water
cut-off and alarm actuation
• Optional features
– Manual reset
– Integral conductance probes for additional levels and
greater operating differential-Model 157S-RBP-MD
– 1" or 1
1
⁄4" NPT equalizing tappings
–
1
⁄2" or
3
⁄4" NPT tappings for gauge glass/tri-cock
installations
– BSPT threads
• Maximum pressure 150 psi (10.5 kg/cm
2
)
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– Prevents nuisance burner shutdowns in 58@9;/<<>;/
applications operating less than 50 psi (3.5 kg/cm
2
)
– For additional information see page 46
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Alarm Circuit Rating (Amperes)
Voltage Amps
120 VAC 1
240 VAC 1/2
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Cut-off and Pump
Circuits Rating (Amperes)
Voltage Full Load Locked Rotor Pilot Duty
120 VAC 7.4 44.4
345 VA at
240 VAC 3.7 22.2
120 or 240 VAC
Model Part Weight
Number Number Description lbs. (kg)
157S 173502 150S low water cut-off w/water column 39.7 (18.0)
157S-MD 173603 157S w/maximum differential 39.7 (18.0)
157S-A 173702 157S w/alternate tappings 39.5 (17.9)
157S-A-M 172811 157S-A w/manual reset 39.5 (17.9)
157S-M 172812 157S w/manual reset 39.7 (18.0)
157S-M-MD 172813 157S-M w/maximum differential 39.7 (18.0)
157S-R 176220 157S w/alternate tappings 42.0 (19.0)
157S-R-M 172817 157S-R w/manual reset 42.0 (19.0)
157S-RBP-MD 176503 157S w/2 integral conductance probes 51.0 (23.1)
157S-RL 176902 157S w/alternate tappings 42.0 (19.0)
157S-RL-M 172815 157S-RL w/manual reset 42.0 (19.0)
Model AB C D E F G H JKL
NPT NPT NPT
157S 1
1
⁄2 13
3
⁄8 (339) 2
5
⁄16 (59) 4
15
⁄16 (125) 11
3
⁄4 (298) 16 (406) 11
1
⁄2 (292) 3
1
⁄2 (89)
3
⁄4 5
7
⁄8 (149)
157S-A 1
1
⁄4
3
⁄4 13
3
⁄8 (339) 2
5
⁄16 (59) 4
15
⁄16 (125) 11
3
⁄4 (298) 16 (406) 11
1
⁄2 (292) 3
1
⁄2 (89)
3
⁄4 5
7
⁄8 (149)
157S-R 1
1
⁄2 13
3
⁄8 (339) 2
1
⁄4 (57) 5
7
⁄8 (149) 11
3
⁄4 (298) 17 (432) 11
1
⁄2 (292) 3
1
⁄2 (89)
3
⁄4 6
1
⁄4 (159)
157S-RL 1
1
⁄4
1
⁄2 13
9
⁄16 (345) 3
1
⁄2 (89) 5
7
⁄8 (149) 11
3
⁄4 (298) 17 (432) 12
3
⁄4 (324) 3
1
⁄2 (89)
3
⁄4 6
1
⁄4 (159)

Boiler Controls
Boiler Controls
®