Xylem MM 206F Series 63 Low Water Cut-Off - Manual (Page 3)

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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-N-
Check (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
VERTICAL RISER TO RADIATION
OR COMPRESSION TANK
HOT WATER
BOILER
TC-4
TC-4
MODEL
63
HOT WATER
BOILER
AVAILABLE OPENING
IN TOP BOILER
AIR
VENT
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).