Reassembly; Over-Temperature Limit Switches - Watts AERCO Edge CFR 3000 Operator's And Service Manual

SECTION 4 INITIAL START-UP
NOTE: These instructions assume the inlet air temperature is between 50°F and 100°F (10°C – 37.8°C). If NOx
readings exceed the target values in Table 4-1 or Table 4-3, increase the O
value, then record the increased O
21. Once the O level is within the specified range at 100%:
2
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Enter the Flame Strength, NOx and CO readings from the Combustion Analyzer and multi-
meter in the Manual Combustion Calibration screen's Reading column.
•
Enter the same values, plus the O
22. Lower the Valve Position to the next calibration point using the  (Left) arrow key (if using Method 1
in step 11) or the Fine Valve Position – (Minus) key (if using Method 2).
•
CFR 3000: 85%
23. Repeat steps 17, 18 and 21 at that valve position and the rest of the valve positions in Table below
corresponding to your model. The O
TABLE 4-3: NATURAL GAS Final Valve Positions
Valve Position
24. If the oxygen level at the lowest valve position is too high, and the Blower voltage is at the minimum
value, you can adjust the TAC screw, which is recessed in the top of the Air/Fuel Valve (see Figure 4-
3). Rotate the screw 1/2 turn clockwise (CW) to add fuel and reduce the O
Recalibration MUST be performed again from 60% or 50% down to the lowest valve position after
making a change to the TAC screw.

4.4 Reassembly

1. Set the Enable/Disable switch to the Disable position.
2. Disconnect AC power from the unit.
3. Shut off the gas supply to the unit.
4. Remove the manometer and barbed fittings and reinstall the NPT plug using a suitable compound.
5. Remove the combustion analyzer probe from the 1/4" vent hole in the exhaust manifold and then
replace the 1/4" NPT plug in the vent hole.
6. Replace all previously removed sheet metal enclosures on the unit.

4.5 Over-Temperature Limit Switches

The unit contains two configurable over-temperature limit controls, positioned behind the unit's front
panel, under the Edge Controller:
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value on the Calibration sheet.
2
value, on the Combustion Calibration Data Sheet provided.
2
, NOx and CO should stay within the ranges shown.
2
O2 %
85% 5.0% ± 0.2%
70% 5.0% ± 0.2%
50% 5.5% ± 0.2%
40% 5.5% ± 0.2%
30% 5.5% ± 0.2%
25% 5.5% ± 0.2%
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level to 1% higher than the Target
2
NOx CO
<100 ppm
≤ 20 ppm
<50 ppm
≤ 20 ppm
<50 ppm
≤ 20 ppm
<50 ppm
≤ 20 ppm
<50 ppm
≤ 20 ppm
<50 ppm
≤ 20 ppm
to the specified level.
2
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