Excelsior DK4EXA075, Установка, эксплуатация и обслуживание

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OPERATING THE BOILER - SYSTEM START-UP
AdJusT oiL BuRneR BeFoRe sTARTinG. (AFG) 1.
Refer to burner manufacturer’s manual for details. A.
Check burner air band, air shutter and head setting B.
(if equipped), readjust if necessary, see Burner Set-
tings section of this manual.
Open all oil line valves. C.
Attach a plastic hose to fuel pump vent fitting and
D.
provide a 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, B.
hold for 30 seconds and release to reset primary
control, if required.
Table 11: L7248A Controller
operating sequence
Action System Response
Thermostat
calls for heat. Circulator starts. Boiler temperature
is checked. Burner starts.
Boiler ex-
ceeds 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.
Turn on burner service switch and allow burner to C.
run until oil flows from vent fitting in a SOLID stream
without air bubbles for approximately 10 seconds.
Close vent fitting and burner flame should start im
- D.
mediately 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 operate but the oil
valve will remain closed. (Refer to Oil Primary Con-
trol Instructions,)
Adjust oil pressure. E.
When checking a fuel unit’s operating pressure, a I.
reliable pressure gauge may be installed in either the
bleeder port or the nozzle port.
Locate oil pressure adjusting screw and turn screw II.
to obtain proper pump pressure, refer to Burner
Settings section of this manual.
To check the cut-off pressure, deadhead a reliable III.
pressure gauge onto the copper connector tube at-
tached 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 IV.
reconnect the nozzle port line.
AdJusT oiL BuRneR WHiLe oPeRATinG. 3.
Adjust Draft Regulator for a breech draft of -0.5 A.
(preferred) to 0 inches water column after chimney
has reached operating temperature and while burner
is running. (At least five minutes) See
Burner Set-
tings section of this manual for details.
Readjust the air band on burner while the breach B.
draft is -0.5 to 0 inches water column (WC). Use
a smoke tester and adjust air for minimum smoke
(not to exceed a trace) with a minimum of excess
air. Make final check using suitable instrumentation
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 adjustments 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.
Turn off burner and remove pressure gauge. Install D.
gauge port/bleeder plug and tighten. Start burner
again.
The switching action in the L7248A control has one set-
ting, 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 auto-
matically rests after the water temperature drops below the
set point minus the differential.