Weil-McLain Evergreen EVG 70 Manual page 97

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Startup — fi nal checks
If combustion at either high or low fi re is
outside the range given in Figure 86, page 98 ,
follow the procedure given on page 96 or
page 98 for adjusting the throttle screw on
the venturi. If throttle screw adjustment
does not correct the problem, then shut
down the boiler and contact your local
Weil-McLain representative. Throttle
screw adjustment must be done only by
a qualified technician, using calibrated
test instruments. Failure to comply could
result in severe personal injury, death or
substantial property damage.
Throttle screw adjustment
EVG 110 ONLY
DO NOT attempt to adjust the throttle screw
unless by a qualifi ed technician, and with the
use of calibrated combustion test instruments.
Adjust the throttle screw only as needed to meet
the combustion values given in Figure 86 .
1. Throttle screw adjustment is
elsewhere in this manual or if combustion tests indicate the
need, as explained under "❏ Check fl ame & combustion
with instruments," page 94.
2. Boiler behavior that might indicate a need to check
combustion values at high fi re (as per page 94 ) to verify
boiler is in adjustment include: diffi culty igniting, poor
fl ame stability at low fi re, combustion noise or high carbon
monoxide values.
3. Combustion readings must be taken at both high fi re and low
fi re. DO NOT attempt an adjustment of the throttle screw
at low fi re. Just check the combustion values.
4. See Figure 84 for location of the
Adjust the throttle screw in small movements.
5. Make sure the Max firing rate is set to the maximum
and confirm the RPM value during operation given in
Figure 90, page 105 . If not, adjust as necessary. Then
navigate to DIAGNOSTICS — Manual test mode (see
Figure 76, page 85 ) and force the fi ring rate to HIGH (high
fi re). After the boiler has had time to stabilize, take a CO
reading. If result is not acceptable, do the following:
a. If the CO is HIGH, turn the throttle screw CLOCKWISE
2
to lower the input. Allow the boiler to stabilize and take
another reading. Continue until the desired CO
is achieved.
Part number 550-100-191/0917
as-fired water boiler —
only necessary if specifi ed
throttle screw.
EVG 110
2
70/110/155
(continued)
Figure 84 EVG 110
a qualifi ed technician, using calibrated
combustion test instruments)
Throttle adjustment screw
b. I f t h e C O
COUNTERCLOCKWISE to increase the input. Allow the
boiler to stabilize and take another reading. Continue until
the desired CO
c. Confi rm that the CO is within limits.
6. Lock the boiler into low fi re. Check the combustion readings. If
results are acceptable at low fi re, verify high fi re readings again.
Restore fi ring rate to AUTO. DO NOT adjust throttle on low fi re.
7. Consult your local Weil-McLain representative if acceptable
results cannot be obtained for both high and low fi re.
2
value
Boiler Manual
Throttle screw (ONLY for use by
i s LOW, t u r n t h e t h r o t t l e s c r e w
2
value is achieved.
2
Gas inlet
pressure
test port
97