Operating Heater; Inspecting Heater - Desa SF20NTX Safety Information And Installation Manual

OPERATING HEATER

Continued
THERMOSTAT CONTROL
OPERATION
The thermostatic control used on these models
differs from standard thermostats. Standard
thermostats simply turn on and off the burner.
The thermostat used on this heater senses the
room temperature. At times the room may
exceed the set temperature. If so, the burner
will shut off. The burner will cycle back on
when room temperature drops below the set
temperature. The control knob can be set to
any heat level between 1 and 5.
amount of gas flow to the burner that increases
or decreases the burner flame height.
Note: The thermostat sensing bulb measures
the 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 will
let you determine your own comfort levels.
MANUAL LIGHTING
PROCEDURE
1. Remove front panel (see Figure 10, page 9).
2. Follow steps 1 through 7 under Lighting
Instructions, 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 seconds
after lighting pilot. After 30 seconds, release
control knob. Now follow step 9, under
Lighting Instructions, page 13.
5. Replace front panel.

INSPECTING HEATER

Check pilot flame pattern and burner flame pat-
tern often.
PILOT FLAME PATTERN
Figure 18 shows a correct pilot flame pattern. Figure
19 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.
14
If pilot flame pattern is incorrect, as shown in
Figure 19
• turn heater off (see To Turn Off Gas to Ap-
• see Troubleshooting, page 16
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.
his adjusts the
T
BURNER FLAME PATTERN
www.desatech.com
pliance, page 13)
Thermocouple
Figure 18 - Correct Pilot Flame Pattern
Thermocouple
Figure 19 - Incorrect Pilot Flame Pattern
WARNING: If yellow tipping
occurs, your heater could pro-
duce increased levels of carbon
monoxide.
NOTICE: Do not mistake orange
flames with yellow tipping. Dirt
or other fine particles enter the
heater and burn causing brief
patches of orange flame.
Blue Pilot Flame
Pilot Burner
Yellow Pilot Flame
Pilot Burner
117933-01A