![background image](http://html1.mh-extra.com/html/desa/hdb20nt/hdb20nt_safety-information-and-installation-manual_2485901017.webp)
www.desatech.com
121254-01A
17
BURNER FLAME PATTERN
WARNING: If yellow tipping
occurs, your heater could pro
-
duce increased levels of carbon
monoxide.
NOTICE: Do not mistake orange
flames with yellow tipping. Dirt
or other fine particles enter the
heater and burn causing brief
patches of orange flame.
Figure 23 shows a correct burner flame pat
-
tern. Figure 24 shows an incorrect burner
flame pattern. The incorrect burner flame
pattern shows yellow tipping of the flame.
It also shows the flame higher than 1/2 the
glass panel height.
If burner flame pattern is incorrect, as shown
in Figure 24
• turn heater off (see
To Turn Off Gas To
Appliance
, page 16)
• see
Troubleshooting
, page 19
INsPeCTING HeATeR
Check pilot flame pattern and burner flame
pattern often.
PILOT FLAME PATTERN
Figure 21 shows a correct pilot flame pattern.
Figure 22 shows an incorrect pilot flame pat
-
tern. The incorrect pilot flame is not touching
the thermocouple. This will cause the thermo
-
couple to cool. When the thermocouple cools,
the heater will shut down.
If pilot flame pattern is incorrect, as shown
in Figure 22
• turn heater off (see
To Turn Off Gas to Ap-
pliance
, page 16)
• see
Troubleshooting
, page 19
Note: The pilot flame on natural gas units will
have a slight curve, but flame should be blue
and have no yellow or orange color.
Figure 23 - Correct Burner Flame Pattern
Yellow
Tipping
Figure 24 - Incorrect Burner Flame
Pattern
1
/
2
Glass
Height
1
/
2
Glass
Height
Blue
Flame
Thermocouple
Pilot Burner
Pilot Burner
Thermocouple
Blue Flame
Yellow Flame
Figure 21 - Correct Pilot Flame Pattern
Figure 22 - Incorrect Pilot Flame Pattern