Weil-McLain WM97+100 Manual page 95

WM97+ Series 2
Startup — fi nal checks
If combustion at either high or low
fi re is outside the range given in
Figure 101, follow the procedure
given on page 95 for WM97+
70 or page 96 for WM97+ 110
or page 97 for WM97+ 155 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.
7. Measure natural gas input:
a. Operate boiler 10 minutes. Turn off other ap-
pliances.
b. At natural gas meter, measure time (in seconds)
required to use one cubic foot of gas.
c. Calculate gas input:
3600 x 1000
number of seconds from step b
d. Btuh calculated should approximate input rat-
ing on boiler rating label.
8. Use the WM97+ control display to navigate to
Manual test mode (see Figure 96, page 86 ) and
change "FORCE RATE" to MIN (low fi re).
9. Look at the fl ame through the fl ame inspection
window. The low fi re fl ame should be stable and
evenly distributed over burner surface with a uni-
form orange color.
10. Repeat the combustion test as instructed in the
previous steps.
11. Use the WM97+ control display to navigate to Man-
ual test mode (see Figure 96, page 86 ) and change
"FORCE RATE" to AUTO (normal operation).
12. Reinstall the fl ue gas temperature sensor. When
replacing the sensor, remove the rubber grommet
from the probe. Insert the rubber grommet into
the fl ue pipe, then insert the probe into the rubber
grommet.
You must reinstall the fl ue gas tempera-
ture sensor to prevent fl ue gas spillage
into the boiler enclosure. Failure to com-
ply could result in severe personal injury,
death or substantial property damage.
Part number 550-142-204/0117
-
GAS FIRED WATER BOILER
(continued)
1. Throttle screw adjustment is
this manual or if combustion tests indicate the need, as explained under
"❏ Check fl ame & combustion with instruments," page 93 .
2. Boiler behavior that might indicate a need to check combustion values
at high fi re (as per page 93 ) 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 103 for location of the
the cover screw to access the throttle adjustment screw.
Figure 103 WM97 +70
Gas inlet pressure test port
= Btuh
Throttle adjustment screw
5. See Figure 92, page 82 . Make sure the Max fi ring rate is set to the
maximum given in the table. If not, adjust as necessary. Then navigate
to DIAGNOSTICS — Manual test mode (see Figure 96, page 86 ) and
force the fi ring rate to MAX (high fi re). After the boiler has had time to
stabilize, take a CO
a. Turn the throttle screw either direction very slightly. Allow the
boiler to stabilize and take another CO
increases or decreases.
b. Turn the screw slightly in the direction needed to increase or decrease
reading as needed. Allow the boiler to stabilize and take another
reading. Continue until CO
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.
— Boiler Manual
Throttle screw adjustment
WM97+ 70 ONLY
DO NOT attempt to adjust the throttle screw unless by a quali-
fi 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 106 .
only necessary
WM97+70
Throttle screw (ONLY for use by a
qualifi ed technician, using calibrated combustion test
instruments)
Adjust the throttle screw in small movements. Turning the
screw too far will cause the adjustment to reverse behavior.
reading. If result is not acceptable, do the following:
2
is acceptable.
2
if specifi ed elsewhere in
throttle screw. Remove
reading. Note whether CO
2 2
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