Lochinvar CREST 3 - Manual (Page 53)

3
Troubleshooting
(continued)
Service Manual
53
Gas valve adjustment procedure
GAS
VALVE 2
GAS
VALVE 1
THROTTLE
THROTTLE
Figure 3-2 Gas Valve Adjustment: Models 1.5 and 2.0
Locate the throttle adjustment screw on the gas valve. For
Models 1.5 and 2.0 see FIG. 3-2, for Model 2.5 see FIG.
3-3 and for Models 3.0 and 3.5 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 52 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 52 or replace the gas valve.
CAUTION
Under normal operating conditions this
valve should not need adjusting.
GAS
VALVE 2
GAS
VALVE 1
THROTTLE
THROTTLE
Figure 3-3 Gas Valve Adjustment: Model 2.5
GAS
VALVE 2
GAS
VALVE 1
THROTTLE
THROTTLE
Figure 3-4 Gas Valve Adjustment: Models 3.0 and 3.5