Reassembly; Over-Temperature Limit Switches - Watts AERCO CFR 1500 Operation And Service Manual

SECTION 4 INITIAL START-UP
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 (CFR 3000)
Valve Position
TABLE 4-4: NATURAL GAS Final Valve Positions (CFR 1500)
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

Two configurable limit controls are positioned behind the unit's front panel, under the Edge Controller:
• Automatic Reset: If the operating temperature exceeds the set limit, the unit goes into alarm
mode and shuts down. When the temperature falls 10° below the limit, the unit automatically
resumes operation. The limit range is 32°F to 200°F (0°C to 93°C). The default 190°F (88°C).
• Manual Reset: If the unit's operating temperature exceeds the set limit, the switch goes into an
alarm mode and shuts the unit down. The unit cannot be restarted until the switch is reset
manually. The limit is preset to 210°F (98.9°C) and should not be changed.
•
, 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%
O2 %
90% 5.5% ± 0.5%
80% 5.5% ± 0.5%
70% 5.5% ± 0.5%
60% 5.5% ± 0.5%
40% 5.5% ± 0.5%
30% 5.5% ± 0.5%
25% 5.5% ± 0.5%
•
NOx CO
≤ 20 ppm <100 ppm
≤ 20 ppm <50 ppm
≤ 20 ppm <50 ppm
≤ 20 ppm <50 ppm
≤ 20 ppm <50 ppm
≤ 20 ppm <50 ppm
NOx CO
≤20 ppm <100 ppm
≤20 ppm <100 ppm
≤20 ppm <50 ppm
≤20 ppm <50 ppm
≤20 ppm <50 ppm
≤20 ppm <50 ppm
≤20 ppm <50 ppm
to the specified level.
2
•