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110772-01 - 5/20
CL
Installation & Service Manual
A. STEAM BOILERS SEQUENCE OF OPERATION
Upon a thermostat call for heat, when provided,
the R8239A Control Center Relay or the Oil
Primary Control is energized when the steam
pressure is below the L404F Pressure Limit and
water level is above the Low Water Cut-Off. When
energized the Oil Primary Control starts the burner
as follows; blower is started and operates for
a pre-purge time; spark is energized and fuel
valve is opened for ignition trail time; the fuel
valve remains open when flame is proven. The
burner fires until the thermostat is satisfied or the
Pressure Limit setting is reached. The Oil Primary
Control stops the burner by closing the fuel valve
and operating the blower for post-purge time.
Upon a drop in pressure, steam pressure below
the L404F Pressure Limit, the burner will re-start
if the thermostat is still calling for heat. When
there is a tankless heater included and there
is no demand for heat, the L4006A operating
control will maintain the boiler water temperature
at the selected setting for proper operation of the
domestic water heater.
The probe low water cut-off will shut down the
burner after a 10 second delay, if the water level in
the boiler drops below the probe level. If the water
level is too low the burner will not be allowed to
restart. The low water cut-off will reset and restart
the burner with a call for heat 30 seconds after the
water is returned to its normal level.
On burner start, if the CAD cell does not see
flame within approximately 15 seconds, primary
control will shut down the burner and enter into a
lockout mode. A lockout is reset by pressing the
reset button located on the primary control. If the
flame is lost while the burner is firing, the primary
control shuts down the burner, enters a 60 second
recycle delay, and repeats the ignition sequence.
If after three (3) trials for ignition, flame is not
detected, primary control will enter into restricted
mode. Restricted mode is reset by holding down
the reset button for 15 seconds.
9
Operating
