Xylem MM 217K User Manual

Series 150S and 157S

(Snap Switch, All Models except 157S-RB-P)

Low Water Cut-Off/Pump Controllers

For Steam Boilers and Other Level Control Applications

Typical Applications:
– Primary or secondary pump controller/

low water fuel cut-off

for steam boilers
– Motorized valve controller
– Low water cut-off
– High water cut-off

INSTRUCTION MANUAL

MM-217K

Series 150S

– Alarm actuator

N

UTIO

CA

NING

R

A

W

•

• Before using this product read and understand instructions.

• Save these instructions for future reference.

• All work must be performed by qualified personnel trained in the proper application, instal-

• To prevent serious burns, the boiler must be cooled to 80˚F (27˚C) and the pressure must be

• 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

• We recommend that secondary (redundant) Low Water Cut-Off controls be installed on all

•

• To prevent a fire, do not use this low water cut-off to switch currents over 7.4A, 1/3 Hp at

•

•

Series 157S

WARNING

!

lation, and maintenance of plumbing, steam, and electrical equipment and/or systems in
accordance with all applicable codes and ordinances.

0 psi (0 bar) before servicing.

installed on the boiler. After installation, check for proper operation of all of the limit and
operating controls, before leaving the site.

steam boilers with heat input greater than 400,000 BTU/hour or operating above 15 psi of
steam pressure. At least two controls should be connected in series with the burner control
circuit to provide safety redundancy protection should the boiler experience a low water
condition. Moreover, at each annual outage, the low water cut-offs should be dismantled,
inspected, cleaned, and checked for proper calibration and performance.
To prevent serious personal injury from steam blow down, connect a drain pipe to the control
opening to avoid exposure to steam discharge.

120 VAC or 3.7A, 1/3 Hp at 240 VAC, unless a starter or relay is used in conjunction with it.

California Proposition 65 warning! This product contains chemicals known to the
state of California to cause cancer and birth defects or other reproductive harm.

Previous controls should never be installed on a new system. Always install new
controls on a new boiler or system.

Failure to follow this warning could cause property damage, personal inj ury or death.

!

2

Approximate

Distance Above

Cast Line Differential

Setting In. (mm) In. (mm)

Pump Off

15

/16(24)

5

/16(8)

Pump On

5

/8(16)

Burner On

5

/8(16)

3

/8(16)

Burner Off

1

/4(6.4)

Pump Off 13/8(41)

3

/4(19)

Pump On

5

/8(16)

Burner On

7

/8(22)

7

/8(22)

Burner Off 0 (0)

OPERATION

Maximum Pressure: 150 psi (10.5 kg/cm2)

Settings and Differential Pressures

Values are ± 8” (3.2mm).

Series 150S, 157S

150 psi (10.5 kg/cm

2

) Levels

150 psi (10.5 kg/cm

2

) Levels

0 psi

(0 kg/

cm2)

150 psi

(10.5 kg/

cm2)

Approximate

Distance Above

Cast Line Differential

Setting In. (mm) In. (mm)

Pump Off

15

/16(24)

3

/8(16)

Pump On

9

/16(14)

Burner Off 0 (0) N/A

Pump Off 17/16(37)

3

/4(19)

Pump On

11/16

(17)

Burner Off - 3/8(-16)

N/A

Model 150S-MD, and 157S-MD

0 psi

(0 kg/

cm2)

150 psi

(10.5 kg/

cm

2

)

Pressure

Pressure

BURNER OFF

BURNER ON

7

/8"

DIFFERENTIAL

(22mm)

PUMP

OFF

BURNER

OFF

NORMAL BOILER

WATER LINE

1

3

/8"

DIFFERENTIAL

(35mm)

PUMP OFF
PUMP ON

3

/4"

DIFFERENTIAL

(19mm)

PUMP OFF
PUMP ON

3

/4"

DIFFERENTIAL

(19mm)

PUMP

OFF

BURNER

OFF

NORMAL BOILER

WATER LINE

1

13

/16"

DIFFERENTIAL

(46mm)

Enclosure rating: NEMA 1 General Purpose

PumpCircuit 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

Electrical Ratings

Alarm Circuit Rating

Voltage Amps

120 VAC 1

240 VAC 1/2

Motor Horsepower

Voltage Hp

120 VAC

1/3

240 VAC 1/3

CAUTION:



A more frequent replacement interval may be necessary based on the condition of

•

the unit at time of inspection. McDonnell Miller s warranty is one (1) year from date
of installation or two (2) years from the date of manufacture.

&

'

3

Approximate

Distance Above

Cast Line Differential

Setting In. (mm) In. (mm)

Motorized

15

/16(24)

Valve Closed

5

/16(8)

Motorized

5

/8(16)

Valve Open

Burner On

5

/8(16)

3

/8(16)

Burner Off

1

/4(6.4)

Motorized 13/8(41)

3

/4(19)

Valve Closed
Motorized

5

/8(16)

Valve Open

Burner On

7

/8(22)

7

/8(22)

Burner Off 0 (0)

Values are ± 8” (3.2mm).

NOTE: Due to the slower operation of some
motorized valves, complete valve opening
or closing will occur at slightly different
levels than indicated above.

Model 158S

150 psi (10.5 kg/cm

2

) Levels

0 psi

(0 kg/

cm2)

150 psi

(10.5 kg/

cm

2

)

Pressure

Settings and Differential Pressures (continued)

150 psi

(10.5 kg/

cm2)

Approximate

Distance Above

Cast Line Differential

Setting In. (mm) In. (mm)

Pump Off

15

/16(24)

3

/8(16)

Pump On

9

/16(14)

Burner Off 0 (0) N/A

Pump Off 17/16(37)

3

/4(19)

Pump On

11/16

(17)

Burner Off -

3/8

(-16)

N/A

Model 158S-MD

0 psi

(0 kg/

cm2)

Pressure

150 psi (10.5 kg/cm2) Levels

NOTE: Due to the slower operation of some
motorized valves, complete valve opening
or closing will occur at slightly different
levels than indicated above.

BURNER OFF

BURNER ON

7

/8"

DIFFERENTIAL

(22mm)

MOTORIZED

VALV E

CLOSED

BURNER

OFF

NORMAL BOILER

WATER LINE

1

3

/8"

DIFFERENTIAL

(35mm)

MOTORIZED

VALV E

CLOSED

MOTORIZED

VALV E

OPEN

3

/4"

DIFFERENTIAL

(19mm)

MOTORIZED

VALVE

OPEN

CLOSED

3

/4"

DIFFERENTIAL

(19mm)

MOTORIZED

VALV E

CLOSED

BURNER

OFF

NORMAL BOILER

WATER LINE

1

13

/16"

DIFFERENTIAL

(46mm)

4

Values are ± 8” (3.2mm).

150 psi (10.5 kg/cm2) Levels

Approximate

Distance Above

Cast Line Differential

Setting In. (mm) In. (mm)

Pump #1 Off15/16(24)

5

/16(8)

Pump #1 On5/8(16)

Pump #2 Off5/8(16)

3

/8(16)

Pump #2 On1/4(6.4)

Pump #1 Off 13/8(41)

3

/4(19)

Pump #1 On5/8(16)

Pump #2 Off7/8(22)

7

/8(22)

Pump #2 On

0 (0)

Model 159S

0 psi

(0 kg/

cm2)

150 psi

(10.5 kg/

cm

2

)

Pressure

Settings and Differential Pressures (continued)

PUMP #1

OFF

PUMP #1

ON

NORMAL BOILER

WATER LINE

(19mm)

3

/4"

DIFFERENTIAL

PUMP #2 ON
AT CAST LINE

7

/8"

DIFFERENTIAL

(22mm)

PUMP #2

ON

PUMP #2

OFF

PUMP #1

OFF

PUMP #2

ON

PUMP #2 ON
AT CAST LINE

NORMAL BOILER

WATER LINE

1

3

/8"

DIFFERENTIAL

(35mm)