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% Power Rate
Figure I-1
30%
Typical
40%
O
levels
2
50%
100%
l. At high fire (end of the modulating motor travel),
adjust the high fire input to match the maximum
input listed on the rating label. Using a flow
meter, the fuel input may be measured using the
following equation,
[Gal end – Gal start] x [3600 sec/hr] /
Oil GPH =
Where Gal end = meter gallons at end of test
Gal start = gallons at start of the test
Measured sec = measured time of test
GPH = Gallons of oil per hour
FIGURE I-2 Typical Atomizing Air Pressure
% Rate
20
30
40
50
100
m. Adjust the NOx level to be about 10% below any
guaranteed NOx performance.
n. Modulate the burner to low fire, adjusting the O
level as the burner modulates.
o. Adjust the low fire input, using the fuel and air
damper adjustments.
p. Re-adjust the midfire points for the correct O
See Figure I-2 for Atomizing Air Pressure.
q. The burner should be operating at low fire to adjust
the air proving switch. Turn the adjusting screw cw
(in) until the burner trips out (shutdown caused by
the air flow switch). Turn the adjustment screw ccw
(out) 1 ½ turns from the point of shutdown. Check
the operation at higher rates.
SC Manual
Natural Gas
< 9 ppm NOx
Min O
Max O
2
8.0
13.0
7.5
11.0
7.0
10.0
6.0
8.0
[measured sec]
Minimum
10 - 25
12 - 30
15 - 35
20 - 40
25 - 60
2
levels.
2
< 30 ppm NOx
Min O
Max %O
2
2
5.0
10.0
4.0
10.0
3.0
10.0
3.0
8.0
6. Operating Control Adjustments
The operating controls must be adjusted to properly
cycle the burner "ON and OFF" and provide modula-
tion. 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 tempera-
ture 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
modulation at some reasonable point below the "ON"
temperature or pressure and provide modulation to
high fire at the lowest temperature or pressure.
7. 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 temperature
or pressure to vary below (or above) the recommended
level to insure that they provide safe shutdown before
the burner operation is affected.
In some high pressure or temperature switches, where
the temperature or pressure cannot be set high enough
to trip the switch, the switch can be checked by lower-
ing the set point to prove that the switch will provide safe
shutdown.
The limit switches include the air proving interlock 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
temperature 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 regularly to ensure
they are operating properly. See the maintenance section.
Page 23
#2 Oil
Min O
Max %O
2
2
3.5
7.5
3.0
7.0
3.0
5.0
3.0
5.0
Startup and Operating Adjustments
2
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