www.desatech.com 117001-01A14INSPECTING HEATERCheck pilot flame pattern and burner flame pat-tern often.PILOT FLAME PATTERNFigure 20 shows a correct pilot flame pattern.Figure 21 shows an incorrect pilot flame pattern.The incorrect pilot flame is not touching thethermocouple. This will cause the thermocoupleto cool. When the thermocouple cools, the heaterwill shut down.If pilot flame pattern is incorrect, as shown inFigure 21• turn heater off (see To Turn Off Gas to Appli-ance, page 13)• see Troubleshooting, page 16OPERATING HEATERContinuedBURNER FLAME PATTERNFigure 22, page 15, shows a correct burner flamepattern. Figure 23, page 15, shows an incorrectburner flame pattern. The incorrect burner flame pat-tern shows yellow tipping of the flame. It also showsthe flame higher than 1/2 the glass panel height.WARNING: If yellow tippingoccurs, your heater could pro-duce increased levels of car-bon monoxide. If burner flamepattern shows yellow tipping,proceed with the following in-structions.NOTICE: Do not mistake orangeflames with yellow tipping. Dustor other fine particles enter theheater and burn causing briefpatches of orange flame.If burner flame pattern is incorrect, as shown inFigure 23, page 15,• turn heater off (see To Turn Off Gas to Appli-ance, page 13)• see Troubleshooting, page 16Thermocouple Pilot BurnerPilot BurnerThermocoupleBlue FlameYellow FlameFigure 20 - Correct Pilot Flame PatternFigure 21 - Incorrect Pilot Flame PatternNote: The pilot flame on natural gas units willhave a slight curve, but flame should be blue andhave no yellow or orange color.THERMOSTAT CONTROLOPERATIONThe thermostatic control used on these modelsdiffers from standard thermostats. Standardthermostats simply turn on and off the burner.The thermostat used on this heater senses theroom temperature. At times the room mayexceed the set temperature. If so, the burnerwill shut off. The burner will cycle back onwhen room temperature drops below the settemperature. The control knob can be set toany heat level between 1 and 5. This adjusts theamount of gas flow to the burner that increasesor decreases the burner flame height.Note: The thermostat sensing bulb measuresthe temperature of air near the heater cabinet.This may not always agree with room tem-perature (depending on housing construction,installation location, room size, open air tem-peratures, etc.) Frequent use of your heater willlet you determine your own comfort levels.MANUAL LIGHTINGPROCEDURE1. Remove front panel (see Figure 10, page 9).2. Follow steps 1 through 7 under LightingInstructions, page 13.3. With control knob pressed in, strike match.Hold match to pilot until pilot lights.4. Keep control knob pressed in for 30 secondsafter lighting pilot. After 30 seconds, releasecontrol knob. Now follow step 9, underLighting Instructions, page 13.5. Replace front panel.