Xylem MM 235E Replacement Snap Switch Assembly SWA 150S 150S MD 158S 159S - Manual (Page 9)

BURNER
SWITCH
BURNER
SET SCREW
K
4b. If the cut-off point does not match the one
as shown in chart for the control (pages 3,
4, or 5) as measured on the "Switch Level
Ruler" dig the inspection lacquer out of the
socket in the set screw (K) above the burner
switch in the actuator assembly using an
awl.
c. Using an Allen wrench with a 5/64" hex, turn
the screw 1/4 turn:
- clockwise (if the “Burner Off” point is too
high when viewed from top)
- counterclockwise (if the “Burner Off” point
is too low when viewed from top)
- for manual reset units with date codes of
03K and newer, the set screw should be
turned opposite the above direction to
obtain desired results.
ADD ADHESIVE HERE M
9
4d. Turn the pump back on, allowing the boiler
to fill with water.
e. Reset the burner switch (L) for manual
reset models once the pump shuts off.
BURNER
“CUT-OFF LEVEL”
AT CAST LINE
BURNER OFF
BURNER ON
4a. Slowly bring the boiler water level down to
the point at which the burner cuts off. If the
burner does not shut off automatically by the
time the water level reaches 3/8" (9.5mm)
below the cast line on the unit body, shut the
burner off manually.
4f. Repeat steps a. through d. as necessary to
match the Burner Off point specification for
your model.
g. Apply one drop of adhesive (furnished) to
the set screw threads (M) above the burner
switch in the actuator assembly.
4 - Setting the Operating Points of the Burner Switch
IMPORTANT: Where Pump On/Off and Burner On/Off are referenced in these instructions, Pump #1 On/Off
and Pump #2 Off/On should be substituted, respectively, for a 159S control, and Motorized Valve
Open/Closed can substitute for Pump On/Off for a 158S control.
L
NOTE
Manual reset units with date codes of 03K and newer require the cover to
be installed for proper operation of the manual reset mechanism.