110021-01BFor more information, visit www.desatech.comFor more information, visit www.desatech.com22Yellow Tipping AtTop of Blue FlamePilot BurnerThermocouplePilot BurnerPilot Burner ThermocoupleBURNER FLAME PATTERNSFigure 39 shows correct front and/or middle burner flame patterns. Figure40 shows incorrect front and/or middle burner flame patterns. Theincorrect burner flame patterns show yellow tipping at top of blue flame.WARNING: If yellow tipping occurs, your heatercould produce increased levels of carbon monoxide. Ifburner flame patterns show yellow tipping, follow in-structions below. Yellow flame on rear burner is normal.NOTICE: Do not mistake orange flames with yellowtipping. Dirt or other fine particles are burned byheater, causing brief patches of orange flame.If front and/or middle burner flame patterns are incorrect, asshown in Figure 40• turn heater off (see To Turn Off Gas to Appliance, page 18 [Ther-mostat-Controlled Models] or page 20 [Remote-Ready Models])• see Troubleshooting, pages 24 through 26INSPECTING BURNERSCheck pilot flame pattern and burner flame patterns often.PILOT FLAME PATTERNFigure 37 shows a correct pilot flame pattern. Figure 38 shows anincorrect pilot flame pattern. The incorrect pilot flame is nottouching the thermocouple. This will cause the thermocouple tocool. When the thermocouple cools, the heater will shut down.If pilot flame pattern is incorrect, as shown in Figure 38• turn heater off (see To Turn Off Gas to Appliance, page 18 [Ther-mostat-Controlled Models] or page 20 [Remote-Ready Models])• see Troubleshooting, pages 24 through 26Note: The pilot flame on natural gas units will have a slight curve,but the flame should be blue and have no yellow or orange color.Figure 39 - Correct Burner Flame PatternsFigure 40 - Incorrect Burner Flame Patterns (VRL Models only)INSPECTING BURNERSPilot Flame PatternBurner Flame PatternsFigure 37 - Correct Pilot Flame Pattern (Your pilot may vary frompilots shown)Figure 38 - Incorrect Pilot Flame Pattern (Your pilot may varyfrom pilots shown)ThermocouplePilot BurnerThermocoupleCorrect Front and Middle Burner Flame Patterns for VRL24NT/PT,VRL24NR/PR, VRL30NT/PT and VRL30NR/PR ModelsIncorrect Front and Middle Burner Flame Patterns forCSG3924NT/PT and CSG3924NR/PR ModelsCorrect Middle Burner Flame Pattern forCTB3924NT/PT and CTB3924NR/PR ModelsIncorrect Front and Middle Burner Flame Patterns for VRL24NT/PT,VRL24NR/PR, VRL30NT/PT and VRL30NR/PR ModelsYellow Tipping AtTop of Blue FlameIncorrect Middle Burner Flame Pattern forCTB3924NT/PT and CTB3924NR/PR ModelsYellow Tipping AtTop of Blue FlameCorrect Front and Middle Burner Flame Patterns forCSG3924NT/PT and CSG3924NR/PR Models(Natural Gas)(Propane/LP Gas)(Propane/LP Gas)(Natural Gas)