TM 5-3895-374-24-2
32.
Set and check operation of:
A)
Low and high gas pressure switches. See gas
pressure switch manufacturer’s instructions for
detailed
procedures.
Units
with
mercury
switching device must be properly leveled.
(1)
For initial start up:
Once the burner’s normal operational gas
pressure has been set, adjust the low and
high gas pressure switches as follows:
(a)
Low gas pressure switch. With the
burner running, slowly close the main gas
train manual shutoff cock and adjust the
switch to open its circuit when the
pressure falls below its normal value.
The burner will shut down. Open the
manual gas shutoff cock to the full open
position and manually reset the Low Gas
Pressure Switch. The burner will restart.
(b)
High gas pressure switch. With the
burner running, adjust the switch to a
point where the switch opens its circuit.
The burner will shut down. Manually
reset the switch and readjust the cutout
point to be made at the normal operating
pressure, but to open if the pressure goes
slightly above normal.
B)
All burner and heat exchanger controls and
operating devices.
C)
Blower Combustion Air Flow Switch
(1)
Shut burner power off.
(2)
Disconnect both wires at the air flow
switch and temporarily clip them together.
Make sure that they cannot ground against
anything, since they will be powered with
110 Volts during the test.
(3)
Put a continuity meter across the common
and normally open terminals on the air
switch.
(4)
Close the gas train checking cock.
(5)
Start the blower motor. The meter should
read electrical continuity as soon as the
blower starts.
(6)
Disconnect the blower motor lead wire or
the wire which energizes coil of motor re
(starter),
or
open
the
main
power
disconnect switch to the burner. Within 4
to 5 seconds after the blower motor is de-
energized, the meter should indicate an
open air flow switch circuit (no continuity).
(7)
If the switch does not open in 4 to 5
seconds, readjust accordingly. Turn the
air flow switch adjustment screw clockwise
to shorten cut-off response time, and
counterclockwise
to
lengthen
cut-off
response time.
(8)
Turn the burner power off. Remove the
shorting clip from the two disconnected
wires and let them hang loose. (They will
be powered with 110 Volts, so don’t let
them ground out.)
(9)
Open the gas train checking cock. Turn
the
burner
on.
With
the
wires
disconnected, the burner should go into a
purge cycle, although neither the ignition
nor the main fuel valve circuits will be
energized. If they do energize, there is a
wiring problem. Correct as required.
(10)
Turn power off. Reconnect the air flow
switch wires to the air flow switch
terminals. Place burner back into normal
operation.
33.
The “Owner's Operating Instructions,” page 43 of
this manual, should be posted in a clearly visible
location close to the burner.
34.
If the burner operation is abnormal, refer to
Section 7, “Trouble Shooting Suggestions,” as
well as trouble shooting information included in
the flame safeguard manufacturer's bulletin
shipped with the burner. It is also strongly
suggested that all test procedures outlined in the
flame safeguard control manufacturer's bulletin be
conducted.
35.
Complete the “Burner Start Up Information and
Test Data” sheets on pages 41 and 42.
6. OIL START UP
Refer to page 21, “General Start Up Procedure - All Fuels” and to
Section 3 for mechanical operation detail of specific mode of
operation. Combination Gas/Oil
systems should also refer to page 22, “Information on Fuel/Air
Modes of Operation for Combination Gas/Oil Units.”
General Information
Power Flame Type C oil burners are of the pressure atomizing
forced draft type, using a single simplex or bypass type nozzle
system. On/Off burners use a simplex nozzle. Fixed air low fire
start burners use a simplex nozzle with a bypass valve to allow
reduced oil nozzle pressures at light off. Low/High/Off and
Low/High/Low burners have movable air dampers and may use a
single simplex or bypass type oil nozzle with a bypass valve to
allow reduced oil pressures at light off and at low fire. Modulating
burners have movable air dampers and use a single simplex or
bypass type oil nozzle with a proportioning metering valve in the
nozzle return line to allow modulated fuel inputs from low to high
fire.
Some applications may require the burner to function at the low
end of its rated capacity. As a result, the two combustion air inlets
may supply more air than is required for efficient combustion. It
may therefore be desirable to operate the system using only one
combustion air inlet and one combustion air inlet damper. This
may be accomplished by removing cross connecting linkage
between dampers and locking the unused damper in a fixed
position.
One way of locking the damper is to use a 10-24 machine screw
through the hole in the linkage arm, and drill and tap the air inlet
housing or use two nuts on the screw and let the screw bear
against the air inlet housing. Air diffuser movement (fore and aft)
may be necessary to produce the best flame pattern or smoothest
operation. See page 20, “Gas, Oil or Gas/Oil Burners Diffuser
Adjustment,” for further information.
Gas and Gas/Oil burners for Scotch marine and other selected
applications incorporate a gas/air premix adjustment. This
adjustment is identified by diametrically opposed adjustment knobs
on the blast tube. See page 20, “Gas or Gas/Oil Burner and
Fuel/Air Premix Adjustment” for further information.
(page 3 - 978)
