Install Instructions

E. MAIN GAS VALVE - OPERATION
1. Figure 5.2 is an illustration of the gas valve/venturi
assembly for the P
UREFIRE
®
boiler.
a. Adjustments should not be made to the gas valve
without instrumentation to measure carbon
dioxide (CO
2
) and carbon monoxide (CO)
emissions in the vent pipe.
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.
30
FUEL PIPING
Figure 5.2: Gas Valve/Venturi
Natural Gas Propane (LP)
Low Fire High Fire Low Fire High Fire
Carbon
Monoxide
(CO)
< 50 ppm < 100 ppm < 50 ppm < 100 ppm
Carbon
Dioxide
(CO
2
)
8.8% to
10.0%
8.5% to
9.5%
9.8% to
11.0%
9.5% to
10.5%
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%
Table 5.4: Recommended CO
2
Settings