Design Dynamics VTD-18N-PDG - Manual (Page 13)

www.desatech.com 111826-02J 13
INSPECtING BURNERS
Check pilot flame pattern and burner flame pat-
terns often.
PILOT FLAME PATTERN
Figure 14 shows a correct pilot flame pattern.
Figure 15 shows an incorrect pilot flame pattern.
The incorrect pilot flame is not touching the
thermocouple. When the thermocouple cools, the
heater will shut down.
If pilot flame pattern is incorrect, as shown in
Figure 15
• turn heater off (see To Turn Off Gas to Appli-
ance, page 12)
• see Troubleshooting, page 15
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 15 - Incorrect Pilot Flame Pattern
(Your Pilot May Differ from Pilots Shown)
Figure 14 - Correct Pilot Flame Pattern
(Your Pilot May Differ from Pilots Shown)
BURNER FLAME PATTERN
Figure 16 shows correct burner flame pattern.
NOTICE: Do not mistake orange
flames with yellow tipping. Dirt
or other fine particles are burned
by heater, causing brief patches
of orange flame.
If burner flame pattern is incorrect, as shown in
Figure 17
• turn appliance off (see To Turn Off Gas to Ap-
pliance, page 12
• see Troubleshooting, page 15
Figure 16 - Correct Burner Flame Pattern
Figure 17 - Incorrect Burner Flame
Pattern
Pilot Burner
Thermocouple
Thermocouple
Pilot Burner
Thermocouple
Thermocouple
Yellow Flames
with Orange
Streaks
Dark Orange
Flames