Procedure B: Fixed Air
(High/Low or High/Off)
1. Be sure combustion air blower is running.
2. Be sure the main gas manual shut off valves are
3. Open adjustable limiting orifice gas cock
fire bypass (if applicable).
4. Open the main gas manual shut off valves.
5. Attempt to ignite burner.
NOTE: Gas solenoid valve
and closed for high/low.
6. If burner does not ignite:
a.Attempt to ignite burner again to purge air from the
b.(High/Low) If burner still does not ignite, turn
adjusting screw 4 a half turn counterclockwise to
increase gas flow.
(High/Off) There is no adjustment.
c.Attempt to ignite burner.
d.Repeat steps a, b and c until burner ignites. If
necessary, refer to Chapter 5 for troubleshooting
Figure 4.7. Adjustable Limiting Orifice, Gas Cock
8. Flame signal strength: Adjust bypass gas flow with
(if applicable) to maintain a stable
flame signal and reliable ignition.
in the low
must be open for high/off
NOTE: If viewing the flame, it should be blue with flashes
of yellow. When firing propane or butane, a proper low fire
flame may have sustained flashes of yellow.
9. Verify low fire flame (if applicable):
a.Shut off gas. Allow process to cool.
b.Verify repeatability of ignition and low fire flame
signal at cold conditions.
10.Shut down the system.
(Low fire by-pass)
1. With burner lit, go to high fire.
2. Wait for the process to reach normal operating
3. Measure high fire fuel differential pressure between tap
"D" and tap "B". Compare this to the "Fuel Orifice ∆P vs.
Input" graph in the datasheet for your burner.
NOTE: If modulating air or gas, adjustment of the control
motor to set high fire gas to the desired input /efficiency
calculated for your process is necessary.
4. Measure high fire air static pressure tap "A". Compare
this pressure to the datasheet for your burner.
5. Go to low fire (if applicable) and verify low fire flame
signal and flame appearance (if viewing).
High-Off (Fixed Air)
High-Low (Fixed Air)