AERCO KC1000 Low NOx Boiler July 2011 - Manual (Page 40)

INITIAL START-UP
4-8
22. Wait for the analyzer to settle and then
compare the new oxygen reading to Table 6
(or 6A). Repeat the inlet air shutter
adjustment until the oxygen is within the
specified range. Also, ensure that the CO
and NOx emissions do not exceed the
values shown. Firmly tighten the inlet air
shutter locking nuts when finished.
REMINDER:
At 30% valve position, adjust only the differential
pressure regulator. At 100% valve position,
adjust only the inlet air shutter.
23. If the measured oxygen reading is above the
oxygen range in Table 6 (or 6A), loosen the
two 7/16" locking nuts securing the inlet air
shutter. Close the air shutter 1/4” to 1/2” to
decrease the oxygen level and tighten the
two nuts.
24. Allow the analyzer to settle then compare
the new oxygen reading to Table 6 (or 6A).
25. Repeat the adjustment until the oxygen is
within the specified range. Also, ensure that
the CO and NOx readings do not exceed the
values shown. Firmly tighten the inlet air
shutter locking nuts when finished.
NOTE:
Adjust the inlet air shutter only at 100% valve
position. Do Not adjust the differential pressure
regulator.
26. Change the valve position to 30%. Allow
time for the combustion analyzer to settle.
Check the measured oxygen level, CO and
NOx emissions to ensure that they are still
within the ranges shown in Table 4.
27. Continue these procedures until all oxygen
levels are within the ranges specified in
Tables 4, 5 and 6 (or 6A).
28. Record all readings on the AERCO start-up
sheet provided with each unit. Proceed to
paragraph 4.5 when all propane combustion
calibration procedures are completed.
4.5 UNIT REASSEMBLY
Once combustion calibration is set properly, the
unit can be re-assembled for permanent
operation.
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 the differential pressure regulator
cap and cap gasket (see Figure 4.3).
4. Apply a drop of silicone adhesive to the
regulator adjusting screw to lock its setting.
5. Reinstall the cap and gasket on the
regulator. Tighten the cap using a
screwdriver or wrench.
6. Remove all of the manometers and barbed
fittings and reinstall the pipe plugs using a
suitable thread compound.
7. Remove the combustion analyzer probe
from the vent hole. Seal the probe hole and
replace the vent connection cover.
8. Replace the unit’s panels and hood.
4.6 OVER TEMPERATURE LIMIT
SWITCH ADJUSTMENTS
There are two Over-Temperature Limit switches
that turn off the unit when the outlet water
temperature becomes too hot. The lower over-
temperature limit switch is adjustable and should
be adjusted 20°F to 40°F above the operating
header temperature. The upper over-
temperature limit switch is a manual reset device
and is not adjustable. It will shut the unit off if the
water temperature reaches 240°F. DO NOT
attempt to adjust its setpoint.
To adjust the lower over temperature switch limit
switch, proceed as follows:
1. Remove the wing nut from the top center of
the shell cap. Lift the cap off the shell.
2. The two over-temperature limit switches are
located at the top of the shell (Figure 4.5).
DO NOT adjust the upper switch which has
been factory preset. Adjust the lower switch
between 20°F to 40°F higher than the
maximum header temperature the unit may
reach.
3. Replace the shell cap and wing nut.