Gas Valve Adjustment Procedure - Lochinvar FTxl 500 Service Manual

3
Troubleshooting

Gas valve adjustment procedure

If adjustment of the gas valve is deemed necessary, use the
following procedures: (Note: The procedures below are
model specific.)
Under normal operating conditions this
CAUTION
valve should not need adjusting.
Models 400 - 500
Locate the throttle adjustment screw on the top of the gas
valve, see FIG.'s 3-3 and 3-4. Using a screwdriver, turn the
screw 1/8 turn counterclockwise to increase CO
or 1/8 turn clockwise to decrease CO
adjustment on the valve, follow the Combustion Analysis
Procedure on pages 47 and 48 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 3-6 on
page 48 or replace the gas valve.
Figure 3-3 Gas Valve Adjustment: Model 400
THROTTLE
ADJUSTMENT
SCREW
Figure 3-4 Gas Valve Adjustment: Model 500
THROTTLE
ADJUSTMENT
SCREW
(continued)
Models 600 - 850
Locate the throttle adjustment screw on top of the gas valve,
see FIG. 3-5. Using an Allen wrench, turn the screw a 1/4
turn counterclockwise to increase CO
clockwise to decrease CO
valve, follow the Combustion Analysis Procedure on pages 47
and 48 of this manual to measure the combustion.
If combustion is still not within the specified range, repeat
levels
2
the procedure. This procedure SHOULD NOT be performed
levels. After one
2
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 3-6 on page 48 or replace the gas
valve.
Figure 3-5 Gas Valve Adjustment: Models 600 - 850
IMG01082
IMG01083
Service Manual
levels or a 1/4 turn
2
levels. After one adjustment on the
2
THROTTLE
ADJUSTMENT
SCREW
IMG01081
49