Xylem MM 231F Series 42/42S Low Water Cut-Offs/Pump Controllers - Manual (Page 9)

STEP 4 - Testing
a. Turn on the electric power to the boiler. With the boiler empty
the pump should go on and the burner must remain off.
IMPORTANT: Follow the boiler manufacturer’s start-up and operating instructions along with all applicable
codes and ordinances.
This control is factory calibrated for specific applica-
tions. The following testing procedure is only meant
to serve as a verification of proper operating
sequence. Dimensions provided are typical for a boiler not being
fired and/or not at pressure. Actual operating ranges
are shown on page 2 in the "Operation" section.
OFF
ON
If the burner comes on, immediately turn the boiler off and make the
necessary corrections.
Failure to follow this warning could cause an explosion or fire and
result in property damage, personal injury or death.
! WARNING
D
(22mm)
7 /
8
"
MM
b. The boiler should begin to fill with water.
Watch the gauge glass (D) until the water
level reaches approximately d” (22mm)
above the horizontal cast line (MM) on the
low water cut-off. When the water level
reaches approximately d” (22mm) the
burner should come on.
IMPORTANT: If water does not start filling the
boiler, immediately turn off the the boiler and
make the necessary corrections.
9
KK
c. Re-attach the junction box cover (KK).