Xylem MM 404J User Manual

Download

Series 93/193 and Series 94/194

WARNING

CAUTION

Low Water Cut-Off/Pump Controllers

For Steam Boilers and Level Control Applications

Typical Applications: – Primary or secondary pump controller/

low water fuel cut-off

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

Series 93 or Series 94

INSTRUCTION MANUAL

MM-404J

Series 193 or Series 194

WARNING

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

• To prevent serious burns, the boiler must be cooled to 80˚F (27˚C) and the pressure must be 0 psi (0 bar) before servicing.

• 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.

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

•

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 cutoffs 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.

• To prevent a fire, do not exceed the switch contact rating.

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.

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.

OPERATION

PUMP

OFF

BURNER

OFF

BURNER “CUT-OFF LEVEL”  AT CAST LINE

/16"

(56mm)

PUMP OFF PUMP ON

(27mm)

/16"

BURNER “CUT-OFF LEVEL”  AT CAST LINE

BURNER OFF

(35mm)

BURNER ON

/8"

BURNER “CUT-OFF LEVEL”  AT CAST LINE

BURNER OFF

(35mm)

BURNER ON

/8"

MOTORIZED

VALVE

CLOSED

BURNER

OFF

BURNER “CUT-OFF LEVEL”  AT CAST LINE

/16"

(56mm)

MOTORIZED

VALVE

CLOSED

MOTORIZED

VALVE

OPEN

(27mm)

/16"

ION

Electrical Ratings

Models with 5 or 5-M Switch

Maximum Pressure: Series 93/193: 150 psi (10.5 kg/cm

Series 94/194: 250 psi (17.6kg/cm

Models with 7B or 7B-M Switch

)

Pump and Burner Switch Contact Ratings

Voltage Pilot Duty Only

120 VA

345 VA

240 VAC

Switch Settings

Values are ±

Models with 5 or 5-M Switches

Setting In. (mm) In. (mm)

Pump Off 23/

Pump On 11/8(29)

Burner On 13/8(35) 13/8(35)

Burner Off 0

” (3mm)

Approximate

Distance Above

Cast Line Differential

(56) 11/16(27)

Switch Ratings

Burner Valve

120 VAC

VA 0 - 135 ohms @ 24 VAC

345

240 VAC

Models with 7B or 7B-M Switches

Approximate

Distance Above

Cast Line Differential

Setting In. (mm) In. (mm)

Valve Full 23/

(56) 11/16(27)

Closed Valve Full 11/8(29)

Open

Burner On 13/8(35) 13/8(35)

Burner Off 0

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

INSTALLATION –

11/2"

STEAM EQUALIZING PIPE

ERTICAL EQUALIZING PIPE

BLOW DOWN VALVE

NORMAL BOILER WATER LINE

AS A PRIMARY LOW WATER CUT-OFF/PUMP CONTROLLER 

BURNER “CUT-OFF LEVEL” A

T CAST LINE

LOWEST PERMISSIBLE  W

ATER LEVEL



WATER

EQUALIZING

PIPE

STEAM EQUALIZING PIPE

VERTICAL EQUALIZING PIPE

BLOW DOWN VALVE

AS A SECONDARY LOW WATER CUT-OFF/PUMP CONTROLLER 

BURNER “CUT-OFF LEVEL” AT CAST LINE

LOWEST PERMISSIBLE  WATER LEVEL

BURNER OFF

WATER

EQUALIZING

PIPE

TOOLS NEEDED:

o (2) pipe wrenches, one (1) flathead screw

Tw driver, and pipe thread dope.

IMPORTANT: Follow the boiler manufacturer's

uctions along with all applicable codes and

instr ordinances for piping, blow-down valve, water gauge glass, tri-cock and electrical requirements.

STEP 1 - Determine the Position of the Low Water Cut-Off/Pump Controller

If the control will be the primary low water fuel cut-off, size the steam (top) and

ater (bottom) equalizing pipe lengths so

w that the horizontal cast line on the body is

1 1/2” (38mm) belo water level, but not lower than the lowest

e permissible water level, as deter-

saf mined by the boiler manufacturer.

If the control will be the secondary low water fuel cut-off, size the steam (top) and

ater (bottom) equalizing pipe lengths so

w that the horizontal cast line on the body is

at or above the lowest safe permissible water le

vel, as determined by the boiler

manufacturer.

w the boiler’s normal

STEP 2 - Installing the Low Water Cut-Off/Pump Controller

11/2"

STEAM EQUALIZING PIPE

ERTICAL EQUALIZING PIPE

BLOW DOWN VALVE

NORMAL BOILER WATER LINE

AS A PRIMARY LOW WATER CUT-OFF/PUMP CONTROLLER 

BURNER “CUT-OFF LEVEL” A

T CAST LINE

LOWEST PERMISSIBLE  W

ATER LEVEL



WATER

EQUALIZING

PIPE

STEAM EQUALIZING PIPE

VERTICAL EQUALIZING PIPE

BLOW DOWN VALVE

AS A SECONDARY LOW WATER CUT-OFF/PUMP CONTROLLER 

BURNER “CUT-OFF LEVEL” AT CAST LINE

LOWEST PERMISSIBLE  WATER LEVEL

BURNER OFF

WATER

EQUALIZING

PIPE

For Series 93/193 or 94/194 (except 94-A, 193-D and 193-G Models)

a. Mount and pipe the control (A) on vertical equalizing

pipes (B) at the required ele

vation as determined in

Step 1. Install a full-ported blow-down valve (C) directly

w the lower cross.

belo

NOTE: 1” (25mm) NPT tappings are provided on Series 93/193 controls.

1 1/4” (32mm) NPT tappings are provided for Series 94/194 controls and 193-B Model.

For 94-A and 193-G Models

a. Mount and pipe the control (A) with a vertical upper

(D) and horizontal lower (E) equalizing piping at the required ele

Install a full-ported blow-down valve (C) on the low body connection.

vation as determined in Step 1.

NOTE: 1 1/4” (32mm) NPT tappings are provided for 94-A Model control.

1” (25mm) NPT tappings are provided for 193-G Model control.

For 193-D Models

a. Mount and pipe the control (A) with a horizontal

upper and lower (G) equalizing piping at the

vation as determined in Step 1.

required ele Install a full-ported blow-down valve (C) on the lo

body connection.

NOTE: 1” (25mm) NPT tappings are provided for 193-D Model control.

wer

STEP 3 - Removing Float Blocking Plugs and Dowels

CAUTION

The plug and rod must be reinstalled before control is shipped installed on the boiler, and removed after boiler is placed and installed.

Failure to follow this caution may damage the float and operating mechanism.

a. Using a pipe wrench, remove the float blocking plugs (I)

and dowels (H) from the control as sho

b. Using a pipe wrench, screw the pipe plugs provided with

control into the open tappings

wn below.

Series 193 / 194

Series 93 / 94

STEP 4 - Installing a Water Gauge Glass and Tri-Cocks

UT-OFF LEVEL

CUT-OFF 

LEVEL

GAUGE GLASS

(TYPICAL)

TRI-COCK (TYPICAL)

NOTE: A separate water column for installation of gauge glass and tri-cocks may be required for boilers

a. Determine pipe size of tri-cock and

sight glass tappings for the control being installed including center distance of sight glass tappings.

NOTE: These items are not provided with control and must be purchased separately

with a Series 93 or Series 94 control. Follow the manufacturer’s instructions to install the water column.

Tri-Cock Gauge Glass Tapping Gauge Glass Tapping

Tapping Pipe Size Center Distance

Unit B C D E F H J K L

193

193-A

193-B

193-D

193-G

194

194-A

194-B

⁄2 (15)

⁄4 (20)

⁄2 (15)

⁄4 (20)

⁄2 (15)

⁄4 (20)

⁄2 (15)

⁄4 (20)

⁄2 (15)

⁄4 (20)

⁄2 (15)

⁄4 (20)

⁄2 (15)

⁄2 (15) 111⁄2 (292)

⁄2 (15) 115⁄8 (295)

⁄2 (15)

⁄4 (20)

⁄2 (15)

⁄4 (20)

⁄2 (15) 123⁄4 (324)

⁄4 (20) 123⁄4 (324)

⁄2 (15) 127⁄8 (327)

⁄4 (20) 127⁄8 (327)

b. Install tri-cocks and gauge glass following

manufacturer’s instructions.

STEP 5 - Electrical Wiring

2 4

1 3

BLUE

BOILER FEED PUMP OFF– BURNER ON–ALARM OFF

BOILER FEED PUMP ON–

BURNER ON–ALARM OFF

BOILER FEED PUMP ON–

BURNER OFF–ALARM ON

RED

3 1

4 2

2 4

1 3

BLUE RED

3 1

4 2

2 4

1 3

LUE RED

3 1

4 2

BLUE

NO. 5

SWITCH

TO BURNERTO PUMP

LINE

123

RED

LINE

ALARM

TRANS.

• To prevent electrical shock, turn off the electrical power before making electrical connections.

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.

Wiring Diagrams

WARNING

NOTE: The following diagrams are provided for reference only.

If available, manufacturer’s wiring diagrams

should always be followed to connect the device being operated.

Switch Operation For Series 93/193 or 94/194 with 5 or 5-M Switch

Red switch terminals 1 and 2 are for burner circuit contacts, terminals 3 and 4 are for the low level alarm circuit contacts.

Blue switch terminals 3 and 4 are for feeder/pump control contacts, terminals 1 and 2 are for high level alarm circuit contacts.

Pump Control, Low Water Cut-Off and Alarm

OW WATER CUT-OFF CIRCUIT

LUE

O. 5

WITCH

URNER

STARTER

LINE

Low Water Cut-Off Only

PUMP CONTROL CIRCUIT

BLUE

NO. 5

SWITCH

PUMP

STARTER

RED

LINE

ALARM CIRCUIT

BLUE

NO. 5

SWITCH

ALARM

TRANS.

NEUTRAL

RED

LINE

2 4

1 3

BLUE

BOILER FEED PUMP OFF– BURNER ON–ALARM OFF

BOILER FEED PUMP ON–

BURNER ON–ALARM OFF

BOILER FEED PUMP ON–

BURNER OFF–ALARM ON

RED

3 1

4 2

2 4

1 3

BLUE RED

3 1

4 2

2 4

1 3

LUE RED

3 1

4 2

BLUE

NO. 5

SWITCH

TO BURNERTO PUMP

LINE

123

RED

LINE

ALARM

TRANS.

Pump Control Only

Low Water Alarm Only

TO BURNER

LINE

432

COMMON

CLOSING CIRCUIT

OPENING CIRCUIT

NO. 7B

SWITCH

BLUE

RED

2 4

1 3

BLUE

BURNER ON–ALARM OFF

VALVE CLOSED

BURNER ON–ALARM OFF

VALVE OPEN

BURNER OFF–ALARM ON

VALVE OPEN

RED

3 1

2 4

1 3

BLUE

RED

3 1

2 4

1 3

BLUE

RED

3 1

For Series 93/193 or 94/194 with 7B or 7B-M

Red terminals 1 and 2 are the burner circuit contacts, terminals 3 and 4 are the low level alarm circuit contacts.

Blue terminal 3 is the common contact, terminals 1 and 4 are the output contacts.

NOTE: The 7B switch is a 135 ohm potentiometer slide wire control for use with an electric valve operator with the same rating.

Proportional Control, Low Water Cut-Off and Alarm

SWITCH

COVER

SWITCH

COVER

Wiring Connections

TO BURNER

LINE

432

COMMON

CLOSING CIRCUIT

OPENING CIRCUIT

NO. 7B

SWITCH

BLUE

RED

2 4

1 3

BLUE

BURNER ON–ALARM OFF

VALVE CLOSED

BURNER ON–ALARM OFF

VALVE OPEN

BURNER OFF–ALARM ON

VALVE OPEN

RED

3 1

2 4

1 3

BLUE

RED

3 1

2 4

1 3

BLUE

RED

3 1

a. Remove two screws (A) and lift off switch

cover.

b. Connect BX armored cable or Thinwall electrical

metal tubing to the integral fitting hub. Connect wires to terminals following appropriate wiring diagram from pages 8 and 9 for your application.

NOTE: Follow local codes and standards when selecting the types of electrical fittings and conduit to connect to control.

c. Replace switch cover and fasten with two

screws (A).

STEP 6 - Testing

TROUBLESHOOTING

– Dimensions shown are typical. – The following testing procedure is only meant to serve

as a verification of proper operating sequence.

a. Turn on power to boiler and pump circuits.

With the boiler empty, the pump should turn on (5 or 5-M switch models) or the valve open (7B or 7B-M switch models). The burner should remain off and boiler should begin to fill with water.

CAUTION

Immediately turn off all power if the burner turns on with no water in the gauge glass. Investigate further before continuing procedure.

b. For Automatic Reset Models

When water level in the gauge glass is approximately 1 3/8” (35mm) above the horizontal cast line, the burner should turn on.

For Manual Reset Models

When water level in the gauge glass is approximately 1 3/8” (35mm) above the horizontal cast line, press the manual reset button and the burner should turn on.

c. For 5 or 5-M Switch Models

When water level in the gauge glass is approximately 2 3/16” (56mm) above the horizontal cast line, the pump should turn off.

For 7B or 7B-M Switch Models

When water level in the gauge glass is approximately 2 3/16” (56mm) above the horizontal cast line, the valve should be closed.

CAUTION

If pump does not turn off or valve close, turn off water supply to boiler. Investigate further before continuing procedure.

d. With the water in the boiler at its normal level and

burner on, SLOWLY open the blow-down valve until it is fully open. As the water level in the gauge glass begins to drop, verify that the following occurs.

For 5 or 5-M Switch Models

When water level drops to approximately 1 1/8” (29mm) above the horizontal cast line, the pump should turn on. When water level drops to the hori zontal cast line, the burner should turn off.

For 7B or 7B-M Switch Models

As the water level drops, the valve should begin to open. When the water level drops to approximately 1 1/8” (29mm) above the horizontal cast line, the valve should be full open. When the water level drops to the horizontal cast line, the burner should turn off.

e. Close the blow-down valve after burner turns off

and restore water level to normal operating level.

f. Repeat testing procedure several times to ensure

proper operation of control.

g. After testing and verification of control operation,

the boiler can be returned to service.

Erratic operation of the control is the most common symptom that occurs. Erratic operation can be defined as pump and/or burner switches not switching at proper levels. Refer to the following list of items to check if the control is not operating properly.

1. Float Ball is Crushed

Crushed floats are typically caused by improper blowdown. Drain piping from blow-down valve to drain should be checked for proper pitch and the blow-down procedure followed when blowing down the control. Purchase and install a new float ball after investigating and correcting the problem.

2. Float Ball is Filled with Water

The seam weld on the float can sometimes deteriorate. This can be caused by the type of chemical treatment used in the boiler. While this is a rare occurrence, the chemical treatment supplier should be consulted to determine if a reaction could occur. Purchase and install a new float ball after investigating and correcting the problem.

3. Float Arm Springs are Bent

The pivot springs located on either side of the float rod should be flat and straight. If they become bent, the usual cause is mishandling of the unit during installation or improper blow-down.The control should never be picked up by the float ball or allowed to hang from the bowl by the float. Drain piping from blow-down valve to drain should be checked for proper pitch and the blow-down procedure followed when blowing down control. Purchase and install new control or head mechanism after investigating and correcting the problem.

4. Switch Contact Springs Broken

The contact springs can break if the electrical rating is exceeded. Purchase and install new switch assembly or head mechanism after investigating and correcting the problem.

5. Switch Contact Springs Misaligned

Misalignment of the contact arms is usually associated with damage to the control during shipment or installation. Purchase and install new switch assembly or head mechanism after investigating and correcting the problem.

6. Internal (Wetted) Parts Dirty

The internal parts can operate improperly if dirt, scale or rust is allowed to build. This condition can be a result of not blowing down the control as recommended and/or improper boiler water chemical treatment. Purchase and install new control or head mechanism after investigating and correcting the problem.

MAINTENANCE

Valve #2

Valve #1

BLOW DOWN PROCEDURE:

SCHEDULE:

Blow down control as follows when boiler is in operation.

• Daily if operating pressure is above 15 psi.

• Weekly if operating pressure is below 15 psi.

NOTE More frequent blow-down may be necessary due to dirty boiler water and/or local codes.

• Remove head assembly and inspect water side components annually. Replace head

assembly if any of the internal components are worn, corroded or damaged or if control no longer operates properly.

• Inspect the float chamber and equalizing piping annually. Remove all sediment and debris.

NOTE The control may need to be inspected and cleaned more frequently on systems where there is the potential of excessive scale or sludge build-up. This includes systems:

• With high raw water make-up

• With no condensate return

• With untreated boiler water

• Where significant changes have been made to the boiler-water chemical treatment process

• With oil in the boiler water

CAUTION

To prevent serious personal injury from steam pipe blow down, connect a drain pipe to the control opening to avoid exposure to steam discharge.

Failure to follow this caution could cause personal injury.

When blowing down a control at pressure, the blow down valves should be opened slowly. The piping needs to be warmed up and stagnant water in the drain piping needs to be pushed out. Suddenly opening a blow down valve causes steam to condense, which creates water hammer. Damage to components can occur when water hammer occurs due to improper blow down piping. For these reasons, McDonnell & Miller recommends a dual valve blow-down system for each control.

Blow down the control when the water in the boiler is at its normal level and the burner is on.

NOTE: Refer to page 2 for switch operating points.

• Open upper valve (#1)

• Slowly open the lower valve (#2)

• Water in the sight glass should lower.

• As the water in the sight glass lowers, the pump should turn on.

• As the water continues to lower in the sight glass, the burner should turn off.

• Slowly close the lower valve (#2).

• Close the upper valve (#1)

• The water level in the sight glass should rise, first

turning on the burner and then turning off the pump. NOTE: On manual reset models, the reset button

will need to be pressed after the water level has been restored before the burner will operate.

Replace head mechanism every 5 years.

More frequent replacement may be required when severe conditions exist.

Replacement parts are available from your local authorized McDonnell & Miller Distributor.

The use of parts or components other than those manufactured by McDonnell & Miller will void all warranties and may affect the units compliance with listings or regulating agencies.

Xylem Inc.

8200 N. Austin Avenue Morton Grove, Illinois 60053 Phone: (847) 966-3700 Fax: (847) 965-8379 www.xyleminc.com/brands/mcdonnellmiller

McDonnell & Miller is a trademark of Xylem Inc. or one of its subsidiaries.

NOTE

If this sequence of operation does not occur as described, immediately close all the valves, turn off the boiler and correct the problem. Inspection/cleaning of the float mechanism may be required to determine why the control was not working properly. Retest the control after the problem has been identified and corrected.

Xylem MM 404J User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual