OPERATING HEATER
Continued
TO TURN OFF GAS
TO APPLIANCE
Shutting Off Heater
Turn control knob clockwise 
to the OFF position.
Shutting Off Burners Only (pilot stays lit)
Turn control knob clockwise 
to the PILOT position.
THERMOSTAT
CONTROL OPERATION
The thermostat control knob can be set to any comfort level between HI and LO. The ther- mostat will gradually modulate the heat output and flame height from higher to lower settings or pilot, in order to maintain the comfort level you select. The ideal comfort setting will vary by household depending upon the amount of space to be heated, the output of the central heating system, etc.
Note: Selecting the HI setting with the control knob will cause the burners to remain fully on, without modulating down in most cases.
MANUAL LIGHTING
PROCEDURE
1.Follow steps 1 through 5 under Lighting Instructions, page 19.
2.Depress control knob and light pilot with match.
3.Keep control knob pressed in for 30 seconds after lighting pilot. After 30 seconds, release control knob. Now follow step 8 under Lighting Instructions, page 19.
INSPECTING BURNERS
Check pilot flame pattern and burner flame pat- terns 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 Figure 28
•turn heater off (see To Turn Off Gas to Appliance, page 18
•see Troubleshooting, page 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.
Pilot Burner 
Thermocouple
Figure 27 - Correct Pilot Flame Pattern (Your pilot may vary from pilots shown)
Pilot Burner
Thermocouple
Figure 28 - Incorrect Pilot Flame Pattern
(Your pilot may vary from pilots shown)
BURNER PRIMARY AIR HOLES
Air is drawn into the burner through the holes in the fitting at the burner entrance. These holes may become blocked with dust or lint. Periodically inspect these holes for any blockage and clean if needed. Blocked air holes will create soot.
MAIN BURNER
Periodically inspect all burner flame holes with the heater running. All slotted burner flame holes should be open with yellow flame present. All round burner flame holes should be open with a small blue flame present. Some burner flame holes may become blocked by debris or rust, with no flame present. If so, turn off heater and let cool. Remove blockage. Blocked burner flame holes will create soot.
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