Service Manual

38
Model 501
Locate the throttle adjustment screw on top of the gas valve,
see FIG. 3-4. 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 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 3-4 Gas Valve Adjustment: Model 501
3 Troubleshooting
Models 601 - 801
Locate the throttle adjustment screw on top of the gas valve,
see FIG. 3-4. Using an Allen wrench, 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 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.
THROTTLE
ADJUSTMENT
SCREW
(REMOVE BLUE CAP)
Figure 3-5 Gas Valve Adjustment: Models 601 - 801
Service Manual