16
Midco International Inc.
8471 95
If the burner is operated at any
fi
ring rate lower than the maximum capacity, there is a possibility to
have too much excess air. See Figure 8.
1. To decrease excess air,
loosen the nut on the air ori
fi
ce
plate and slide it inward.
2. To increase excess air, slide it
outward.
The VA series burner is designed
to operate as low as 1% O
2
(5%
excess air). It is not recommended
to adjust the excess air without
using a combustion analyzer.
F
-
Excess Air
Adjustment
VI Initial
Start-up/Adjustment
Continued
Slide
One Way or
the Other
Loosen the Nut
Figure 8 -
Excess Air Adjustment
Part 1 Installation
__________________________________________
1. Check the operation of the burner; start and stop it several times with the operating control.
2. With the burner running, check the operation of all limit and associated controls.
3. Perform the following
fi
nal adjustments for combustion and
fl
ue gas temperature. Take the
fl
ue
gas samples and temperature immediately upstream of the draft control. Generally, the
fl
ue gas
temperature should be above 325°F but not exceeding 550°F. Excessive
fl
ue gas temperatures will
result in low e
ffi
ciencies. Low
fl
ue gas temperature may cause excessive condensation. Reset gas
input, if necessary, to adjust stack temperature.
4. Check the draft control, if equipped, to make sure there is no spillage of
fl
ue products into the
room.
5. Fill out the installation adjustment data tag and a
ffi
x to the burner or gas utilization equipment.
NOTE:
For subsequent normal starting and shut o
ff
procedure, refer to CONSUMER
INSTRUCTIONS, located in Section XX of this manual, or to the instruction plate mounted
on the burner.
__________________________________________
-
Use a combustion analyzer to con
fi
rm that the high
fi
re oxygen (O
2
) level is between
3.0 to 5.0% and the carbon dioxide (CO
2
) level is between 8.5 to 10.0%. The carbon
monoxide (CO) should be less than 100 ppm corrected to 3% O
2
while the
fl
ue gas
temperature should be below 550° F.
-
Con
fi
rm that at low
fi
re the oxygen level is between 16.0 to 18.5% and the carbon
monoxide (CO) level is less than 400 ppm corrected to 3% O
2
.
_____________________________________
-
Remove call for heat (open heat enable contact).
-
Close main supply gas valve, see Figure 3 - item # 2 page 4.
-
Turn
o
ff
main power disconnect and burner control panel switch.
-
Remove pressure tap
fi
ttings and gauges for pressure measurements. Replace pipe plugs.
-
Reinstall the caps to the pilot regulator, main regulator, low-
fi
re bypass and ratio regulator.
_____________________________________
-
Open all manual gas valves
-
Turn on power at disconnect switch
-
Turn on power switch on burner control panel door
-
Set heat enable and temperature controller to desired operating condition and temperature
-
Burner will start and operate based on 2 to 10V DC analog input provided
_____________________________________
G
-
Final Checks
VII Check Emissions
24V Burners
VIII Shut Downs
24V Burners
I X Normal
Operations
24V Burners