Direct Fired Burner Ignition - Weather-Rite XT112 Installation, Operation & Service Manual

S XT I , O
ERIES NSTALLATION PERATION AND
FIGURE 29: Midco HMA-2A Burner

18.1 Direct Fired Burner Ignition

The burner that is used in the Weather-Rite LLC unit
is equipped with a pilot assembly. The pilot assembly
consists of a pilot gas tube, spark electrode or rod
and a flame rod with grounding assembly. For proper
ignition the spark rod must be adjusted correctly. A
FIGURE 30: Spark Rod Dimensions
WARNING: the ignition system on the air handler generates between 6,000 to 10,000 volts.
The gas supplied to the pilot gas tube should be 3 1/
2" wc for natural gas and between 9 to 11" wc for
propane or LP. The difference between the two fuels
is that a restricting orifice is installed in the propane
or LP pilot gas tube. The pilot assembly can be used
on propane or LP without an orifice, if this is the case
then the pressure for LP is 2.0"w.c. Ignition will take
place with the introduction of gas to the pilot gas
56
S M
ERVICE ANUAL
A
B
C
E
A B
in 2.940 0.125
cm 7.468 0.318
high voltage arc is generated between the spark rod
and the pilot gas tube. The gas flowing out the ports
in the pilot gas tube is ignited by this arc. The arc will
be a brilliant electric blue in color. See Page 56,
Figure 29.
D
C D E
0.125 1.881 0.633
0.318 4.778 1.608
tube. The pilot flame will be mostly blue in color with
streaks of yellow. The flame size will be roughly 2" in
diameter. The flame must be steady and consistent
in size.