42
ADJUST OIL BURNER BEFORE STARTING. (AFG)
1.
NOTICE
These instructions are for Beckett AFG. For other burners, refer
to the manufacturer’s manual. The nozzle and air setings are
given in Table 14. For direct vent installation guide, see Direct
Vent Addendum.
Refer to burner manufacturer’s manual for details.
A.
Check burner air band, air shutter and head setting (if
B.
equipped), readjust if necessary, see
Burner Settings
section
of this manual.
Open all oil line valves.
C.
Table 11: L7248A Controller
Operating Sequence
Action
System Response
Thermostat calls
for heat.
Circulator starts. Boiler temperature
is checked. Burner starts.
Boiler exceeds
the high limit.
Burner is turned off. Burner restarts
when the water temperature drops
below the high limit setting minus the
differential.
Thermostat is
satisfied.
Circulator and burner turned off.
Burner (AFG) post-purge is 15
Error
Condition
If an error condition is detected, all
outputs are shut down. Burner is
off. Control continues to function
and restarts when error is corrected.
During the error check sequence, the
system checks for drift in the sensor
and corrosion in the connections.
Attach a plastic hose to fuel pump vent fitting and provide a
D.
pan to catch the oil.
START OIL BURNER
2.
Open vent fitting on fuel pump. (See
A.
Pump Priming Cycle,
4.B.II)
Press red reset button on front of oil primary cover, hold for 30
B.
seconds and release to reset primary control, if required.
Turn on burner service switch and allow burner to run until oil
C.
flows from vent fitting in a SOLID stream without air bubbles
for approximately 10 seconds.
Close vent fitting and burner flame should start immediately
D.
after pre-purge is completed. Pre-purge prevents burner flame
until 15 seconds has elapsed after initial power is applied to
burner. During pre-purge the motor and igniter will oper-
ate but the oil valve will remain closed. (Refer to Oil Primary
Control Instructions,)
Adjust oil pressure.
E.
When checking a fuel unit’s operating pressure, a reliable pres-
I.
sure gauge may be installed in either the bleeder port or the
nozzle port.
Locate oil pressure adjusting screw and turn screw to obtain
II.
proper pump pressure, refer to
Burner Settings
section of
this manual.
To check the cut-off pressure, deadhead a reliable pressure
III.
gauge onto the copper connector tube attached to the nozzle
port. Run the burner for a short period of time. Shut the
burner off. The pressure should drop and hold.
Remove the gauge and install bleeder port and/or reconnect
IV.
the nozzle port line.
ADJUST OIL BURNER WHILE OPERATING.
3.
Adjust Draft Regulator for a breech draft of -0.5 (preferred) to
A.
0 inches water column after chimney has reached operating
temperature and while burner is running. (At least five min-
utes) See
Burner Settings
section of this manual for details.
Readjust the air band on burner while the breach draft is -0.5
B.
to 0 inches water column (WC). Use a smoke tester and adjust
air for minimum smoke (not to exceed a trace) with a mini-
mum of excess air. Make final check using suitable instru-
mentation to obtain a CO
2
of 11.5 to 13%. These settings will
assure a safe and efficient operating condition. If the flame
appears stringy instead of solid fire, try another nozzle of the
same type. Flame should be solid and compact. After all adjust-
ments are made, recheck for a draft in the breach. See
Burner
Settings
section of this manual.
Re-adjust the head setting only if necessary.
C.
The switching action in the L7248A control has one setting, the
high limit. The switching relay is controlled by the low voltage room
thermostat. On a call for heat, the relay contacts close to complete
the line voltage circulator circuit and also the burner circuit if the
boiler water temperature is below the high limit setting. The high
limit switch shuts off the burner if boiler water temperature exceeds
the high limit setting. The circulator will continue to operate as long
as the thermostat is calling for heat. The high limit automatically
rests after the water temperature drops below the set point minus the
differential.
OPerATiNg THe BOiLer - SYSTeM STArT-UP
