Xylem MM 715B Series 63 64/764 and 65/165 Replacement Floats - Manual (Page 4)

a. Turn the boiler on.
b. Fill the control and check for gasket leakage.
c. Slowly open the blow-down valve which will
lower the water level in the float chamber.
When the water level drops to the horizontal
cast line, the burner should turn off. Close the
blow- down valve after the burner turns off
and restore the water level to normal operating
level. Repeat testing procedure several times to
ensure proper operation of control.
After testing and verification of control operation,
the boiler can be returned to service.
CAUTION
Immediately turn off all power if the burner turns on with
no water in the gauge glass. Investigate further before
continuing procedure.
!
MAINTENANCE
SCHEDULE:
• Blow down control as follows when boiler is in
operation.
• Steam:
— Daily if operating pressure is above 15 psi.
— Weekly if operating pressure is below 15 psi.
• Hot Water:
— Quarterly
• Disassemble and inspect annually. Replace the
low water cut-off if it is worn, corroded, or if
components no longer operate properly.
• Inspect the float chamber and equalizing piping
annually. Remove all sediment and debris.
• Replace head mechanism every 5 years.
More frequent replacement may be required
when severe conditions exist such as rapid switch
cycling, surging water levels, and use of water
treatment chemicals.
• We recommend head mechanism replacement
when the switch(es) no longer operate properly.
If you choose to replace the switch(es), order the
proper McDonnell & Miller replacement switch or
switch assembly and follow the repair procedure
provided.
PROCEDURE:
Blow down the low water cut-off when the water
level is at the normal level and the burner is on.
Slowly open the blow down valve until it is fully
open and observe the water level fall in the gauge
glass. Close the valve after verifying that the pump
contacts have closed and the burner shuts off. If this
does not happen, immediately shut off the boiler
and correct the problem.
NOTE
More frequent blow-down may be necessary due to
dirty water and/or local codes.
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.
! CAUTION
OFF
ON
STEP 2 - Testing the Control
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.
© 2012 Xylem Inc. MM-715B August 2012 Part No. 246001