INITIAL START-UP
4-5
NOTE:
Adjust the inlet air shutter only at 100% firing
rate. Do not adjust the differential pressure
regulator.
25. Change the firing rate to 30%. Allow time for
the combustion analyzer to settle. Check the
measured oxygen reading to insure that it is
still within the range as per Table 1.
26. Continue this procedure until all oxygen
levels are within the ranges specified in
Tables 1, 2 and 3.
27. Record all readings on the AERCO start-up
sheet provided with each unit. Proceed to
paragraph 4.5.
4.4 PROPANE COMBUSTION
CALIBRATION
For propane units it will be necessary to install
an additional 8” W.C. manometer. This
manometer will be used to measure the
pressure drop across the air/propane mixing
orifice. After performing the setup procedures in
paragraphs 4,2.2 through 4.2.4, install the 8”
W.C. manometer as described in steps 1, 2 and
3 which follow.
1. Referring to Fig. 4.5, remove the 1/8” NPT
plug from the gas inlet pipe ahead of the
burner and install a 1/8” NPT barbed fitting.
2. Remove the 1/2” NPT plug from the tee
located after the air pressure regulator and
install a 1/2” barbed fitting (see fig. 4.5).
3. Attach the 8” W.C. manometer to the barbed
fittings installed in steps 1 and 2.
NOTE:
The combustion calibration data in Tables 1, 2
and 3 apply to both natural gas and propane
units. Therefore, refer to these Tables when
performing propane combustion calibration.
4. While performing the combustion calibration
procedure in paragraph 4.3, measure the
pressure drop across the air/propane mixing
orifice using the 0-8” W.C. manometer.
5. This reading should remain a constant 3.8”
to 4” W.C. throughout the operating range.
6. If the pressure drop is not within this range,
remove the cap from the air pressure regula-
tor.
7. Using a flat blade screwdriver adjust the
regulator until 3.8”-4.0” W.C. is obtained.
Clockwise will increase the reading and
counter-clockwise will decrease the reading.
8. If adjustments are made to this regulator it
will be necessary to recheck oxygen settings
at 16%, 30%, and 100% firing rates.
NOTE:
After an adjustment is made to the air regulator,
the cap must be put back on securely to obtain
an accurate reading.
Figure 4.5
Propane Air Differential Pressure Taps
4.5 UNIT REASSEMBLY
Once combustion calibration is set properly, the
unit can be re-assembled for permanent opera-
tion.
1. Set the ON/OFF switch to the OFF position.
Disconnect the AC power supply from the
unit.
2. Shut off the gas supply to the unit.
3. Remove any regulator adjustment tools by
first pulling up the screwdriver blade to
disengage it from the regulator adjusting
screw, and then turning the tool out of the
top of the regulator.
4. Apply a drop of silicone to the regulator
adjusting screw to lock its setting.
5. Remove the gasket from the tool and place it
back onto the regulator cap.
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