Xylem MM 413F Replacement Head Mechanism With Switch Assembly: 93-HD, 93-M-HD, 93-7B-HD, 93-7B-M-HD, 94-HD 94-M-HD 94-7B-HD 94-7B-M-HD - Manual

INSTRUCTION MANUAL
MM-413F
Head Mechanism
with Switch Assembly
Head Mechanism
without Switch Assembly
Replacement head mechanisms can be
installed without disturbing existing equalizing
connections or disassembly of components,
making repair simple and easy.
Replacement Head Mechanism
With Switch Assembly:
93-HD, 94-HD
93-M-HD, 94-M-HD
93-7B-HD, 94-7B-HD
93-7B-M-HD, 94-7B-M-HD
Without Switch Assembly:
93-HDLS 94-HDLS
• 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-
lation, 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
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.
Failure to follow this warning could cause property damage, personal injury or death.
WARN ING
CAUT ION
! WARNING