Xylem MM 206F User Manual
Series 63
Low Water Cut-Off
Typical Applications:
- Primary or secondary low water cut-off
for hot water and steam boilers.
- Low water cut-off
- High water cut-off
- Alarm actuator
OPERATION
Maximum Boiler Pressure: 50 psi (3.5 kg/cm2)
Electrical Ratings
Motor Switch Rating (Amperes)
Voltage
120 VAC 10.2
240 VAC 5.1 30.6
Full Load Locked Rotor
61.2 125 VA at
Pilot Duty
120 or 240 VAC
INSTRUCTION MANUAL
MM-206F
CUT OFF
LEVEL
Model 63
WARNING
!
CAUTION
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 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.
• To prevent a fire, do not use this low water cut-off to switch currents over 10.2A, 1/2 Hp at
120 VAC or 5.1A, 1/2 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.
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.
!
&
'
Gauge Glass Mounted
Directly into Boiler
CUT-OFF
LEVEL
1" BLOW DOWN
VALVE
For Boilers with
Independent Water Columns
1" STEAM
EQUALIZING PIPE
MODEL 63
LOW WATER
CUT-OFF
1" WATER
EQUALIZING PIPE
1" WATER
EQUALIZING PIPE
1" WATER
EQUALIZING PIPE
CUT-OFF
LEVEL
MODEL 63
LOW WATER
CUT-OFF
2
a. Whether the gauge glass is mounted directly into the boiler or on an independent water column, the
cut-off line on the 63 body casting should be mounted 1/2” (15mm) above the lowest visible point of the
gauge glass.
a. Locate the gauge glass and
determine the level that the 63
has to be mounted at in order
to achieve the criteria in Step 1.
b. Pipe the 63 following the
diagrams shown to the right.
Follow the diagram that
represents your boiler.
c. Crosses should be used at
each right angle connection for
inspection and cleaning.
d. Make sure the blow-down
valves are full port.
e. While the burner is operating,
open the blow-down valve,
causing the water level to drop in
the float chamber while burner is
operating. As the float drops the
alarm circuit (if used) closes first;
then on further drop the cut-off
circuit will open, shutting the
burner off.
f. Test the Model 63 before leaving
the site.
STEP 2 - Installation of the Model 63
Model 63 – For Steam Boilers with 1” (25mm) Equalizing Lines
INSTALLATION –
TOOLS NEEDED:
One (1) flathead screwdriver and two (2) pipe wrenches.
STEP 1 - Determine the Location of the Low Water Cut-Off
For 63 models with float block
CUT OFF
LEVEL
A
Using pipe wrench
• Remove float blocking plug (A) from low
water cut-off body tapping.
• Screw 3/4” NPT steel plug (provided) in
tapping.
3
a. The line on the casting of the model 63 must be installed above the lowest permissible water level
determined by the boiler manufacturer.
a. Study the figures to the right and determine which
figure shows how the 63 control will be attached to
the boiler.
Figure 1. Connect the upper equalizing pipe to
the riser going to the radiation or to the compression
tank. Connect the lower equalizing pipe to any
available opening in the side of the boiler. NOTE: If
no opening is available in the side of the boiler,
connect the lower equalizing pipe into the drain
connection.
Figure 2. If there is a tapping available on the
top of the boiler, connect the upper equalizing pipe to
it. NOTE: During initial filling or after blow-down the
upper equalizing pipe and possibly the 63 control will
have an air pocket. Connect a vent or bleed valve on
the top of the vertical equalizing pipe. If the Test-NCheck (TC-4) valve is used the vacuum breaker can
be used to bleed the air pocket.
CAUTION: When bleeding an air pocket manually,
protect yourself from being burned with hot water.
Figure 3. If there is no tapping available on the boiler,
connect both the upper and lower equalizing pipe
into the vertical riser going to the radiation or to the
compression tank. IMPORTANT: The horizontal equalizing
pipe should be below the horizontal run going to the
radiation. If it is not, an air pocket will be created and
a vent or bleed will have to be installed.
b.
While the burner is operating open the blow-down
valve, causing the water level to drop in the float
chamber. As the float drops the alarm circuit (if used)
closes first; then on further drop the cut-off circuit will
open, shutting the burner off.
c. Test the Model 63 before leaving the site.
STEP 2 - Installation of the Model 63
Model 63 – For Hot Water Boilers with 1” (25mm) Equalizing Lines
INSTALLATION –
TOOLS NEEDED: One (1) flathead screwdriver and two (2) pipe wrenches.
For float type controls it is recommended that Test-N-Check
®
(TC-4) valves be used in the upper and
lower equalizing lines. They offer a functional means for testing the 63 control, and conform to the
ASME CSD-1 code.
STEP 1 - Determine the Location of the Low Water Cut-Off
VERTICAL RISER
TO RADIATION
HOT WATER
BOILER
MODEL
63
Figure 1
Figure 2
Figure 3
For 63 models with float block
CUT OFF
LEVEL
A
Using pipe wrench
• Remove float blocking plug (A) from low
water cut-off body tapping.
• Screw 3/4” NPT steel plug (provided) in
tapping (A).
VERTICAL RISER TO RADIATION
OR COMPRESSION TANK
TC-4
AVAILABLE OPENING
IN TOP BOILER
AIR
VENT
HOT WATER
BOILER
MODEL
63
HOT WATER
BOILER
MODEL
TC-4
63
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