User Guide

37
3 Troubleshooting (continued)
Gas valve adjustment procedure
If adjustment of the gas valve is deemed necessary, use the
following procedure:
Locate the throttle adjustment screw on the side of the
venturi valve (FIG. 3-2). Using a screwdriver, turn the screw
a 1/4 turn counterclockwise to increase CO
2
levels or a 1/4
turn clockwise to decrease CO
2
levels. After performing
one adjustment on the valve, follow the Combustion
Analysis Procedure on page 36 of this manual to measure the
combustion.
If combustion is still not within the specified range, repeat
the procedure. This procedure SHOULD NOT be performed
more than four (4) times. If after four (4) adjustments and
the combustion is still not within the specified range, revisit
the possible causes in Table 3H on page 36 or replace the gas
valve.
Figure 3-2 Gas Valve Adjustment
Service Manual
THROTTLE
ADJUSTMENT
SCREW