Vanguard Heating VN18A - Manual (Page 18)

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GRH/OV 008 BAD PILOT/LP
GRH/OV 007 GOOD PILOT/LP
Thermocouple
Pilot Burner
Pilot Burner
Thermocouple
Blue Flame
Yellow Flame
Figure 27 - Correct Pilot Flame Pattern
Figure 28 - Incorrect Pilot Flame Pattern
Figure 29 - Correct Burner Flame Pattern
INSPECTING HEATER
Check pilot flame pattern and burner flame pat-
tern often.
PILOT FLAME PATTERN
Figure 27 shows a correct pilot flame pattern. Figure
28 shows an incorrect pilot flame pattern. The incor-
rect pilot flame is not touching the thermocouple.
This will cause the thermocouple to cool. When the
thermocouple cools, the heater will shut down.
If pilot flame pattern is incorrect, as shown in Fig-
ure 28
• turn heater off (see To Turn Off Gas to Appli-
ance, page 15 or 17, depending on your model)
• see Troubleshooting, pages 20 through 22
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 30 - Incorrect Burner Flame
Pattern
BURNER FLAME PATTERN
Figure 29 shows a correct burner flame pattern.
Figure 30 shows an incorrect burner flame pattern.
If burner flame pattern is incorrect, as shown in
Figure 30
• turn heater off (see To Turn Off Gas to Appli-
ance, page 15 or 17, depending on your model)
• see Troubleshooting, pages 20 through 22
Bad Burner Pattern-Plaque GRH/OV 019