507148-01
Page 11 of 14
Issue 1406
9. Recheck draft and CO
2
reading at the service hole in
the flue outlet.
10. Using a suitable thermometer, obtain and record the flue
gas temperature at the service hole in the flue outlet.
11. Use the CO
2
reading and the flue gas temperature
reading to determine unit efficiency.
12. When the proper combustion and smoke readings have
been achieved, tighten the air shutter screw(s) and air
band screws that were loosened in Step 5.
Nozzle and Electrode Alignment
Proper nozzle and electrode depth and alignment are
essential for proper burner operation.
To check and adjust the nozzle depth:
1. Insert the small end of the “T” gauge into the end of the
cone and measure from the flat of the end cone to the
tip of the nozzle. The proper measurement should be
1.13”. When the depth is correct, the tip of the nozzle
should just touch the base of the “T” gauge.
2. Nozzle adjustments are made by sliding the entire
nozzle assembly forward or backward within the blast
tube.
To check nozzle alignment:
1. Insert the small end of the “T” gauge into the end of the
cone and measure the nozzle and electrode alignment
against the center lines marked on the gauge.
2. If nozzle is not centered, but found to be too far left or right,
a new nozzle will need to be ordered.
Do not attempt to
adjust by bending the 90° elbow in oil line.
Sequence of Operation
Heating (see Figure 13 on page 12)
The thermostat calls for heat, activating the burner motor. After a
15-second pre-purge period, power is sent to the burner and
ignition is established. When the burner pump reaches full
speed, the solenoid valve is energized. After the thermostat
is satisfied, the thermostat circuit opens. The solenoid valve
is de-energized before the pump rotation stops. Power to
the burner is interrupted, shutting down the burner.
Cooling
Unit is set up at the factory for single stage cooling. For two
stage cooling operation, the jumper wire running from Y1
to Y2 on the blower interface board must be clipped and
removed. See Figure 17 on page 14 for two stage cooling
wiring.
If the active dehumidification feature is enabled, the
circulating blower runs at 82% of the selected cooling speed
OPERATION
Figure 11
Set the NX
tip position
by aligning
the electrode
top with the
mark shown
in Figure 12.
Set the electrode
tip gap spacing
(5/32”) by adjusting
the tips to meet the
two out side marks
shown in Figure
13. Make sure the
tips are centered
about the nozzle
centerline.
Figure 12
