Profire V Burner Chapter 2
750-177 2-25
The burner should be set up and maintained to yield smoke spot levels less than a #1 spot (ASTM D2156
Shell-Bacharach Scale) to minimize soot buildup in the boiler.
Do not disturb established low fire adjustment. Allow the burner to re
turn to low fire position before adjusting
high or intermediate settings.
When conditions covered above are assured, refer to NORMAL OPERA
TION below.
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.
Refer to the Gas Burner or Oil Burner adjustment procedures.
Once the adjustments are set for oil, shut down the burner
and restart the adjust the natural gas fuel. DO NOT
READJUST THE AIR DAMPERS. The adjustment is made by balancing the fuel input rate against the existing
flow of combustion air.
When conditions covered above are assured, refer to NORMAL OPERA
TION below.
Note: SIZE 1 & 2 COMBINATION GAS/OIL UNITS USE A DIRECT COUPLING FROM THE BLOWER MOTOR
TO THE OIL PUMP. WHEN FIRING GAS FOR AN EXTENDED PERIOD OF TIME, THE COUPLING SHOULD BE
MANUALLLY REMOVED AND REPLACED ONLY WHEN FIRING OIL. IF THE COUPLING IS LEFT CONNECTED
TO THE BLOWER MOTOR, ENSURE THAT THERE IS PROPER OIL CIRCULATION AT ALL TIMES TO AVOID
DAMAGE AND SEIZURE OF THE PUMP.
NORMAL OPERATION
Normal operation must be with the MANUAL-AUTO switch selector on AUTO.
In automatic operation, the operating
cycle always proceeds sequentially through pre-purge, pilot ignition,
main flame ignition, run and post-purge. The length of purge and ignition trial vary according to the type of
programmer used.
During the run cycle, burner input is regulated to the load
demand by the modulating pressure or temperature
control on the boiler. The burner will continue to modulate until the operating pressure or temperature is
reached.
Programmer control operation should be tested when the burner i
s initially placed into service, when a control
is replaced, and at scheduled intervals in the maintenance program.
SHUTDOWN
When the operating limit control setting is reached or the burner switch is turned OFF
, the following sequence
occurs:
1. The fuel valve(s) de-energize and flame extinguishes. The blower motor continues running during post-purge (if so
equipped with post-purge feature).
2. At the end of the post-purge the blowe
r motor is de-energized. The programmer returns to its starting position and
stops. Unit is ready to restart.
Abnormal shutdown might result from motor overload flame outage, low water, current or fuel supply
interruption, combustion or atomizing air pressure below minimum level, tripped circuit breakers, blown fuses,
or other interlock devices. Check for cause and correct before restarting burner.
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