PEERLESS PUREFIRE PFW-199, Installation, Operation & Maintenance Manual, Page: 28 / 81

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b. Turning the throttle screw clockwise will decrease
the gas flow (decreasing CO
2
) and turning it
counterclockwise will increase the gas flow rate
(increasing CO
2
). Markings adjacent to the throttle
screw show + and – indicating this operation.
c. The recommended CO
2
settings are given in Table
5.4. In no case should the boiler be allowed to
operate with CO emissions above 150 ppm.
2. Refer to Section 3, Venting and Air Intake for
information on obtaining vent samples from this boiler.
FUEL PIPING
Table 5.4: Recommended Combustion Settings
Natural Gas LP Gas
Low Fire High Fire Low Fire High Fire
Carbon Dioxide (CO
2
) 8.8% to 10.0% 8.5% to 9.5% 9.8% to 11.0% 9.5% to 10.5%
Carbon Monoxide (CO) < 50 ppm < 100 ppm < 50 ppm < 100 ppm
Excess Oxygen (O
2
) 3.4% to 5.4% 4.2% to 6.0% 4.2% to 6.0% 4.9% to 6.5%
Excess Air 17.3% to 31.0% 22.4% to 35.8% 22.4% to 35.8% 27.3% to 40.1%