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3. Using the 16" manometer installed as per
Section 4.2.1, adjust the gas supply
regulator until a reading of 12" W.C. static
pressure is obtained.
4. Place the green ON/OFF switch in the OFF
position. Turn on AC power to the unit. The
temperature controller and annunciator
displays should light.
5. Put the temperature controller in manual
mode
NOTE:
For a review of control panel operating
procedures, see Section 3.
6. Change the firing rate (Pct) to 0.0%.
7. Place the green ON/OFF switch in the ON
position.
8. Change the firing rate (Pct) to 25%. This will
put the unit into the starting sequence.
NOTE:
On initial start-up or return to service from a
fault condition, a warm-up timer of 2
minutes is activated by the controller. This
prevents the BTU input from exceeding
400,000 BTUs/HR even though the control
signal may indicate a greater input.
9. Observing the 2 minute warm-up period
increase the firing rate in 10 % increments
while monitoring the gas pressure after
every increase. If gas pressure dips below
8.5" W.C. for FM gas trains and 8.9" for IRI
gas trains at any input percentage, stop and
raise the pressure. Once 100% is reached,
adjust the gas pressure for 8.5" W.C. or 8.9"
W.C.
NOTE:
If 8.5" W.C. for FM gas trains or 8.9" W.C.
for IRI gas trains cannot be obtained at the
100% firing rate, it will be necessary to stop
calibration and contact the local AERCO
representative in your area. Running the
unit on insufficient gas pressure will void the
warranty
10. Once 8.5" W.C. or 8.9" W.C. is set at the
100% level change the firing rate (Pct) to
30%. Insert the combustion analyzer probe
into the stack.
Always go to a percentage of firing rate from
the same direction, (i.e., 100% to 30% or
30% to 20%). Whenever going to a firing
rate from below (i.e., 20% to 30%), first go
above then back down to the desired firing
rate. This is necessary due to hysteresis in
the air/fuel stepper motor. Hysteresis
causes the air/fuel valve to stop in a slightly
different position if the firing rate percentage
is approached from below or above. This
results in a difference in oxygen readings for
the same firing rate percentage causing
unnecessary recalibration.
11. Allow enough time for the combustion
analyzer to settle. Compare the measured
oxygen level to the oxygen range for intake
air temperature in Table 1.
Inlet Air
Temp
Oxygen
o
20
F
5.7 %
o
40
F
o
60
F
o
80
F
o
100
F
Combustion Oxygen Levels for a 30%
Firing Rate
12. If the measured oxygen level is within the
range in Table 1, no adjustment is
necessary. Proceed to step 17.
13. If the measured oxygen level is below the
range in Table 1, rotate the differential
regulator adjustment tool counter clockwise
1/4-1/2 revolution to decrease gas flow.
14. Wait for the combustion analyzer to settle,
then compare the new oxygen reading to
Table 1. Repeat adjustment until oxygen is
within the specified range.
15. If the measured oxygen level is above the
oxygen range in Table 1, rotate the
differential regulator adjustment tool
clockwise 1/4-1/2 revolution to increase gas
flow.
20
INITIAL START-UP
NOTE:
Table 1
Carbon
Monoxide
<50ppm
5.5 %
<50ppm
5.2 %
<50ppm
5.0 %
<50ppm
4.9 %
<50ppm
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