Weil-McLain UO-3 CV, Instruction Manual

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16
Allow the burner to run for approximately 5 to 10
minutes.
1.
Step 2:
At the trace of smoke level, measure the
CO
2
(or O
2
) . This is the vital reference
point for further adjustments. Example:
13.5% CO
2
(2.6% O
2
)
Step 3:
Increase the air to reduce the CO
2
by 1.5 to
2 percentage points. (O
2
will be increased
by approximately 2.0 to 2.7 percentage
points.) Example: Reduce CO
2
from
13.5% to 11.5% (2.6% to 5.3% O
2
).
Step 4:
Recheck smoke level. It should be Zero.
This procedure provides a margin of
reserve air to accommodate variable
conditions.
If the draft level has changed, recheck the
smoke and CO
2
levels and readjust
burner, if necessary.
Step 5:
Once the combustion has been set, tighten
the lower acorn nut and splined nut on the
air adjustment assembly. See Figure 9.
Chimney Vent Systems: Install the burner cover
and repeat Steps 2 and 4 above. If CO
2
increases
(O
2
decreases), remove the cover and adjust the
air setting so the CO
2
(O
2
) with the cover installed
meets the requirements of Step 3.
Direct Vent Systems with outside air ducted to
burner: Install the burner cover.
Start and stop the burner several times to ensure
satisfactory operation. Test the primary control
and all other appliance safety controls to verify
that they function according to the manufacturer’s
speci
fi cations.
4.
5.
6.
Figure 10. – Nozzle Line/Head/Air Tube Assembly (Low fi ring rate shown.)
Retention Head Retention Head
Head Support Legs Head Support Legs
Electrode Tips Electrode Tips
Electrode Clamp Electrode Clamp
Electrode Bracket Electrode Bracket
Electrode Insulator Electrode Insulator
Electrode Extension Rods Electrode Extension Rods
Nozzle Adapter Nozzle Adapter
Nozzle Nozzle
Stops in Retention Ring Stops in Retention Ring
Retention Ring Retention Ring
Throttle Ring Throttle Ring
Throttle Cup Throttle Cup
Nozzle Line Nozzle Line
Bulkhead Fitting Bulkhead Fitting
SK9666A SK9666A
Throttle Cup Hub Throttle Cup Hub
Set the stack or over- fi re draft to the level speci fi ed
by the appliance manufacturer.
Natural Draft Applications;
typically over- fi re
draft is -0.01” or -0.02” w.c.
Direct Venting
; typically may not require draft
adjustment.
High Effi ciency/Positive Pressure Appliances
;
also vary from traditional appliances (see
manufacturer’s recommendations).
Follow these fi ve steps to properly adjust the
burner:
Step 1:
Adjust the head/air until a trace of smoke
is achieved. This can be accomplished
by turning the screw on the head/air
adjustment plate assembly to increase air
(CCW) or decrease air (CW).
2.
○
○
○
3.
The NX burner has a reduced
diameter air tube, precision-
designed air throttle cup and combustion head
for improved performance. This design provides
very accurate control of the air/fuel ratio, but the
light reaching the cad cell through small holes in
these components is limited. Because of this,
the
average cad cell resistance may be higher than
conventional burners
with larger openings.
Section: Start the Burner and Set Combustion