Burner Adjustments - CleaverBrooks FLX Operation, Service And Parts Manual

Profire V Burner
flame is obtained and a satisfactory low-fire oil flame is
established. Turn burner off and restart to ensure smooth
ignition is obtained at the set low-fire pressure. Replace
knurled nut and hand tighten.
4. Adjust the high-fire oil input to match the maximum rat-
ing. Turn the burner off and reconnect the wiring to the
solenoid valve. Restart the burner and allow burner to
go through ignition and low-fire. When the solenoid
energized, the oil pump discharge pressure is at high-fire
pressure. The high-fire pressure adjustment screw is
located on the oil pump body. Adjust the screw, clock-
wise to increase the pressure and counterclockwise to
decrease the pressure, until correct amount of oil pres-
sure is obtained. The high-fire oil pressure should be
300 PSI. High-fire is typically 3.5% to 4.5% O
less than a No. 1 smoke. The burner should be adjusted
to provide the correct amount of fuel flow at a constant
rate at high-fire position as indicated on the burner data
plate, located inside the control panel.
COMBINATION GAS-OIL BURNERS
In general, the combination fueled system is to be started first
using oil, because as a fuel, oil has a greater combustion air
requirement than natural gas. After being completely
adjusted for oil combustion, the burner is restarted and
adjusted using natural gas as fuel. Combustion adjustment of
the combination burner for natural gas involves balancing the
input rate only against the existing flow of combustion air, as
established initially for oil.
Do not readjust the air shutters when turning the
combination burner for combustion of natural gas.
1. Turn the fuel selector switch to the "Oil" position.
2. Turn the burner switch to the "On" position.
3. Proceed with startup and adjustments using the same
procedures defined in the Oil Burners section.
4. After the system has been completely adjusted for oil
firing, place the burner switch "Off" and position the
fuel selector switch to "Gas."
5. Proceed with startup and adjustments using the same
procedures defined in the Gas Burners section. Do not
alter the air settings set for oil.
:
Notice
FOR BURNERS EQUIPPED WITH A
SIEMENS MODULATING MOTOR, FUEL/AIR
ADJUSTMENTS FOR EACH FUEL ARE INDEPEN-
DENT OF EACH OTHER. REFER TO SIEMENS
MODULATING MOTOR PRODUCT LITERATURE
FOR PROPER ADJUSTMENT.
750-177
L O W- H I G H - O F F & L O W- H I G H - L O W

BURNER ADJUSTMENTS

Refer to the burner data plate located inside the control panel
door. The data plate will list the burner information: burner
and control voltage, phase, cycle, motor amperage, maximum
and minimum fuel input settings, manifold pressure (at zero
furnace pressure). Add the furnace pressure to get the correct
manifold pressure at maximum firing rate.
These procedures assume that the pre-startup tasks, checklist,
electrical interference test, and pilot turndown tests have been
performed in accordance with the instructions in this manual.
Allow boiler to fully warm up before making adjustments for
most efficient combustion. Refer to the boiler instruction
with
manual for the boiler control settings.
2
GAS BURNERS
The gas burner adjustments on a Low-High-Off system
consist of the gas pressure regulator, gas butterfly valve, low
and high gas pressure switches, and air damper assembly.
The auxiliary switch inside the M436 Mod motor makes or
breaks the High fire gas. The Low-High-Low boiler control
energizes the M436 motor, driving it to high-fire. When the
boiler control de-energizes the M436, a built-in return spring
drives it to the low-fire position.
All VG-13 to 55 use a butterfly gas valve to control the gas
flow to the burner. The M436 Mod motor controls the
position of the valve.
1. Open the manual gas shutoff cocks.
2. Check the gas pressure at the inlet of the regulator and
the pressure downstream of the regulator. Make sure
they are in accordance with the regulator specifications.
The gas pressure required at the manifold is the pressure
that is required to fire the burner at its rated capacity. To
adjust the regulator, unscrew the cap located on top and
turn the adjustment screw clockwise to increase pres-
sure, or counterclockwise to decrease pressure.
3. Turn the burner switch to the "On" position.
4. The burner will start and be in the low-fire position.
5. After a few seconds, the O
accurate reading of the O
mally, O
for standard turndown systems on gas and 6% to 9% O
for high turndown systems, with the target value of less
than 50 ppm CO. To obtain the proper readings, adjust
the air shutter and low-fire regulator pressure.
6. Operate the boiler at low-fire until it is up to operating
pressure (steam) or temperature (hot water).
7. Bring the burner to the high-fire position. Adjust the
high-fire gas input to match maximum rating. At high-
fire, the butterfly valve should be near the full open
analyzer should have an
2
present in the flue gas. Nor-
2
levels are set between 4% to 6% at low-fire
2
Chapter 2
2
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