Section: BURNER START-UP
24
Burner Start-up
Explosion, Fire, and
Asphyxiation Hazard
Professional Installation & Service
Required. Incorrect installation an
d set up
c
ould lead to equipment malfunction.
Asphyxiation Hazard
It is recommended that you measure the oxygen
(O
2
) early in the test sequence because high levels
of carbon monoxide (CO) can be created at very
low or very high O
2
levels. The typical operating
range is between 3%-5% O
2
.
This burner must be installed and prepared for start-up by a
qualified service technician who is trained and experienced
in gas burner system installation and operation.
Do not attempt to start the burner unless you are
fully qualified.
Do not continue with this procedure without the proper
test instruments.
Carefully follow the wiring diagrams, control instruction
sheets, control sequence of operation, test procedures
and all appliance manufacturer’s directions that pertain
to this installation.
Test Instruments
The following calibrated test equipment is required to
properly install the appliance. They should be calibrated
and in good working order.
|
A combustion analyzer capable of measuring
oxygen (or carbon dioxide), carbon monoxide,
stack temperature, ambient temperature, and
appliance efficiency.
|
Electrical multi-meter capable of measuring voltage,
ohms, amps, and DC micro-amps for measuring the
flame signal.
|
Calibrated manometers and pressure gauges
capable of measuring all pressure ranges in the gas
supply and appliance draft. This could typically range
from a few PSI to 0.1” W.C.
Burner Start Procedure
(Before proceeding, turn off and lock out electrical
power and close the main shut off cock to shut off
gas to the burner.)
1. With the power and main gas supply to the burner
turned off, make sure gas has not accumulated in the
boiler or flues.
2. Check the initial air settings (shutter & band) for input
firing rate. See
on page 25 for initial air
settings.
3. With the main shutoff cock closed. Set the limit or
controller to call for heat then apply power to start the
burner.
4.
Verify Burner Safety Control Function
– In order
to check the function of each component (i.e.: 7590
sequence, airflow proving switch, ignition transformer,
gas valves, safety lockout timing, etc.), with the main
shutoff cock closed, monitor a complete burner run
sequence. Note that the 7590C control will enter a
5 minute waiting time after failing the trial for ignition
since the fuel supply has been closed off. Reset the
control by pressing and holding the reset button while
the control is powered.
5.
Verify Flame Sensor Function
– If 7590 operation
sequence and function is correct, turn off power and
remove sensor wire from bottom of 7590 control.
Turn on power and fuel and initiate Call for Heat.
Verify that burner fires up and the gas valve closes.
After control locks out, flame shall go off.
6. Turn power off and reattach sensor wire. Turn power
back on and reset the control using reset button.
Initiate Call for Heat.
7. After you have observed main flame for a brief time,
press the reset button on the control for 1 second to
shut down and re-start the burner. Monitor the flame
and safety shutoff valves to assure that shutdown
is controlled by the valves and that they operate
properly. With this test passed, you may safely initiate
automatic start-ups on subsequent cycles.
8. While the burner is firing, examine the vent system
for evidence of leaks, obstructions, and for correct
function of the barometric draft control. Leak test all
gas piping from the burner to the utility supply piping.
If leaks are found, correct them immediately.
9.
Low gas pressure switch
– With the burner firing
and a manometer attached to a test port near the low
pressure switch, gradually close the main leak test
cock to shut off the gas supply. Note the pressure at
which the low gas pressure switch opens and shuts
the burner off. Manually reset the switch. The low gas
pressure switch should be set at half of the normal
supply pressure in the line.
10.
High gas pressure switch
– With the burner firing
and a manometer attached to the test port nearest
the high pressure switch, gradually increase the gas
pressure until the high pressure switch opens and
shuts the burner off. Note the pressure and manually
reset the switch. The high gas pressure switch should
be set at one and one half times the high fire manifold
pressure (see nameplate data in
Figure 1
or set
switch as determined by testing).
