Webster JB Series Installation, Startup, Operation And Maintenance Manual page 37

Figure I-3
O2 levels
z. 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 1/2 turns
from the point of shutdown. Check the operation at higher
rates.
11. Pressure Atomized Oil Setup
The pressure atomized oil system has a limited range of
adjustment for low and high fire, dictated by the operation
of the oil nozzle. The combustion air and FGR must be
adjusted to match these rates.
If the burner is equipped with FGR, and is a linkage sys-
tem, the type of FGR control must be determined prior
to starting. If this is a dual fuel burner, the FGR rate is
determined by the NOx performance on gas. A 60 ppm
burner will operate with the same FGR rate on gas and oil.
A 30 ppm unit will use the limiting potentiometer to slightly
reduce the FGR rate on oil firing. For Oil only combustion,
the NOx level will be given on the burner detail sheet, and
should be used to set the FGR control valve.
a. Place the burner switch in the "OFF" position.
b. Place the "Auto-Manual" switch in the manual position
or low fire hold switch in the low fire position fo LO-HI-LO
operation. If this is a combination fuel burner, make sure
the fuel selector switch is on "OIL".
c. Place the manual flame control potentiometer in the
min (low fire) position on modulation units.
d. Turn the electrical power for the burner, boiler and re-
lated components on.
e. Verify that the oil metering valve is nearly opened (the
valve will be closed at high fire).
f. Turn the burner switch on. This will start the blower mo-
tor and initiate the purge cycle.
g. When the prepurge sequence is complete and the low
fire start switch (if used) is made, the pilot valve will open
and the pilot flame should be visible through the burner
sight port.
h. When the pilot flame is established, the flame safe-
guard will energize the main oil valves (indicated with the
Fuel Valve Light), and the burner should ignite at low fire.
This operation of the main fuel valves must be visually
checked by observing the valve stem moving up with a
motorized valve or hearing the clicking noise from a sole-
noid valve.
NOTE: If the burner is not operating as indicated, follow
the troubleshooting steps to determine the problem and
corrective action.
i. The main flame may not light on the first attempt, be-
JB Manual
Natural Gas
With FGR
% Rate Min Max
% O2 % O2
30 5.0 7.0
40 4.0 7.0
50 3.0 5.0
100 3.0 5.0
cause it must fill the oil lines before providing oil to the
nozzle. Press the reset button on the flame safeguard to
restart the burner.
DO NOT ATTEMPT TO START THE BURNER WHEN EXCESS OIL
HAS ACCUMULATED, WHEN THE UNIT IS FULL OF VAPOR, OR
WHEN THE COMBUSTION CHAMBER IS HOT.
j. After a few seconds, the combustion analyzer should
have an accurate reading of the O2 in the stack. The O2
level should be between 4% and 7%, and the nozzle oil
pressure should be between 50 and 70 PSIG return line
pressure for the JB3. JB1 and JB2 burner low fire oil pres-
sure should be 100 psig. Do not attempt to fine tune com-
bustion until the high fire has been set.
If the burner is equipped with FGR, the FGR control valve
should be set for the approximate NOx level required.
1. Turning the cam screw in will add fuel, making it richer
and reducing the O2 level.
2. Turning the cam screw out will reduce the fuel input,
increasing the O2 level.
3. The air damper should be positioned for the correct
low fire settings.
k. Operate the burner until the boiler is warmed up, and
near the operating pressure or temperature.
l. Increase the firing rate, using the manual potentiom-
eter or put the low fire hold switch in auto position, while
monitoring and adjusting the O2 level. Adjust the cam as
needed to reach the high fire input.
If the burner is equipped with FGR, adjust the FGR control
valve as required to maintain the NOx level.
m. At high fire (end of the modulating motor travel), adjust
the high fire input (open or close the fuel valve) to match
the maximum input and/or pressure listed on the rating
label. The fuel metering valve should be nearly closed
(or closed) at this point and the nozzle pressure should
be about 150 PSIG (return line) for JB3. For JB1 and JB2
250 to 300 psig.
n. If equipped with FGR, adjust the NOx level to be about
10% below any guaranteed NOx performance or if perfor-
mance guarantee exists adjust the FGR to provide some
added turbulence but not high enough to impact flame sta-
bility. A balance of the FGR control valve and air damper
are required to obtain the final result, as each can impact
the other. If this is a 30 ppm system, the FGR limiting pot
should be adjusted to reduce the FGR rate for stable com-
bustion, with the FGR control valve set when firing gas. If
this is a 60 ppm system, no adjustment is necessary.
o. Modulate the burner to low fire, adjusting the O2 level
as the burner modulates.
Page 37
Natural Gas
No FGR
Min Max Min
%O2 %O2 %O2
5.0 7.0 3.5
4.0 7.0 3.0
3.0 5.0 3.0
3.0 5.0 3.0
WARNING
Startup and Operating Adjustments
Oil
Max
%O2
7.5
7.0
5.0
5.0