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4. Operating Control Adjustments
The operating controls must be adjusted to properly
cycle the burner "ON and OFF" and provide modulation.
The controls should not force the burner into rapid "ON-
OFF" cycles, as this will cause premature failure of the
motor and operating equipment.
The operating control must be adjusted to provide the
"ON" pressure or temperature desired. It must allow the
burner to come on and start before the temperature or
pressure drops into the modulating range. The "OFF"
pressure or temperature must be sufficiently above the
"ON" point to allow a reasonable run time.
The modulating control must be adjusted to start modu-
lation at some reasonable point below the "ON" temper-
ature or pressure and provide modulation to high fire at
the lowest temperature or pressure.
5. Limit Tests
Once the burner has been started and the operating
pressures and temperatures have been set, the limit
switches need to be adjusted so that they will trip if the
pressure or temperature exceeds the operating value,
but will not trip with normal variations. The switch should
be checked for proper operation by allowing the temper-
ature or pressure to vary below (or above) the recom-
mended level to insure that they provide safe shutdown
before the burner operation is affected. In some high
pressure or temperature switches, where the tempera-
ture or pressure cannot be set high enough to trip the
switch, the switch can be checked by lowering the set
point to prove that the switch will provide a safe shut-
down.
The limit switches would include the air proving switch
on the burner. Limits for gas operation could include the
high and low gas pressure switches and for oil firing, the
high and low oil pressure switches, high and low oil tem-
perature switches and the atomizing air pressure switch.
If in doubt about which limits are on a burner, refer to the
wiring diagram that will show each item.
Limit switches need to be checked at regular intervals
to ensure they are operating properly. See the mainte-
nance section for details.
SG Manual
6. Burner Shutdown
Normal operation of the burner will allow the operating con-
trols to shut the burner down when the load demand is sat-
isfied. If the burner needs to be shut down for any reason,
the "ON-OFF" switch can be used to quickly turn the burner
off. This will instantly cause the fuel valves to close and
start a post purge cycle to remove any unburned fuel from
the vessel.
In an emergency shutdown, all fuel and electrical power
should be de-energized or turned off to secure the burner.
This would include the main power disconnect, the manual
gas shutoff valve at the drop down line and if equipped, the
manual oil valve to the nozzle.
It is recommended that the burner be manually driven to
low fire before turning the burner off, as this reduces the
dynamic and thermal stress. If the burner will remain off for
some time, the manual fuel valves, fuel pumps and power
supply should be turned off.
ALWAYS KEEP THE FUEL SUPPLY VALVE SHUT OFF WHEN THE
BURNER IS SHUT DOWN FOR AN EXTENDED PERIOD OF TIME.
7. Restarting after Extended Shutdown
Extended shutdowns require the same startup process as
those outlined above. In addition, the following advanced
cleaning must be done,
a. The air atomized oil nozzle should be removed and
cleaned, if pressure atomized they should be replaced.
Use care in cleaning to preserve the sharp edges of the
nozzle, which are required to maintain good atomization.
b. The oil filter and strainer must be removed and cleaned
prior to starting.
DO NOT START THE BURNER UNLESS ALL CLEANOUT DOORS
ARE SECURED IN PLACE.
Page 15
CAUTION
CAUTION
Startup and Operating Adjustments
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