Desa FAS-3C - Manual (Page 14)

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INFRARED NATURAL GAS HEATER
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 tempera-
ture. The temperature setting knob can be
set to any comfort level between 1 and 7.
Note: The thermostat sensing bulb mea-
sures the temperature of air near the
heater cabinet. This may not always agree
with room temperature (depending on
housing construction, installation loca-
tion, room size, open air temperatures,
etc.) Frequent use of your heater will let
you determine your own comfort levels.
INSPECTING
BURNER
Check pilot flame pattern and burner flame
pattern often.
PILOT FLAME PATTERN
Figure 23 shows a correct pilot flame pattern.
Figure 24 shows an incorrect pilot flame
pattern. The incorrect pilot flame is not touch-
ing the thermocouple. This will cause the
thermocouple to cool. When the thermo-
couple cools, the heater will shut down.
If pilot flame pattern is incorrect, as shown
in Figure 24
• turn heater off (see To Turn Off Gas to Ap-
pliance, page 12 for non-thermostat mod-
els or page 13 for thermostat models)
• see Troubleshooting, pages 15 through 17
GRH/OV 009 GOOD PILOT
Figure 23 - Correct Pilot Flame Pattern
Thermocouple
GRH/OV 010 BAD PILOT
Thermocouple
Figure 24 - Incorrect Pilot Flame Pattern
Pilot Burner
Pilot Burner
Figure 25 - Correct Burner Flame Pattern
Bad Burner Pattern-Plaque GRH/OV 019
Figure 26- Incorrect Burner Flame Pattern
CLEANING AND
MAINTENANCE
CAUTION: You must keep
control areas, burner, and circu-
lating air passageways of heater
clean. Inspect these areas of
heater before each use. Have
heater inspected yearly by a quali-
fied service person. Heater may
need more frequent cleaning due
to excessive lint from carpeting,
bedding material, pet hair, etc.
WARNING: Turn off heater
and let cool before servicing.
OPERATING
HEATER
Continued
MANUAL LIGHTING
PROCEDURE
1. Follow steps 1 through 5 under Light-
ing Instructions, page 13.
2. With control knob pressed in,
strike match. Hold match to pilot
until pilot lights.
3. Keep control knob pressed in for 30
seconds after lighting pilot. After 30
seconds, release control knob.
BURNER FLAME PATTERN
Figure 25 shows a correct burner flame
pattern. Figure 26 shows an incorrect burner
flame pattern.
If pilot flame pattern is incorrect, as shown
in Figure 26
• turn heater off (see To Turn Off Gas to Ap-
pliance, page 12 for non-thermostat mod-
els or page 13 for thermostat models)
• see Troubleshooting, pages 15 through 17
ODS/PILOT AND BURNER
• Use a vacuum cleaner, pressurized air,
or small, soft bristled brush to clean.
CLEANING BURNER
PILOT AIR INLET HOLE
We recommend that you clean the unit every
2,500 hours of operation or every three months.
We also recommend that you keep the burner
tube and pilot assembly clean and free of dust
and dirt. To clean these parts we recommend
using compressed air no greater than 30 PSI.
Your local computer store, hardware store, or
home center may carry compressed air in a
can. You can use a vacuum cleaner in the
blow position. If using compressed air in a
can, please follow the directions on the can.
If you don't follow directions on the can, you
could damage the pilot assembly.
1. Shut off the unit, including the pilot.
Allow the unit to cool for at least thirty
minutes.
2. Inspect burner, pilot for dust and dirt.
3. Blow air through the ports/slots and
holes in the burner.
Clean the pilot assembly also. A yellow tip
on the pilot flame indicates dust and dirt in
the pilot assembly. There is a small pilot air
inlet hole about two inches from where the
pilot flame comes out of the pilot assembly
(see Figure 27). With the unit off, lightly
blow air through the air inlet hole. You may
blow through a drinking straw if compressed
air is not available.
Figure 27 - Pilot Inlet Air Hole
Pilot Assembly
Pilot Air Inlet
Hole
CABINET
Air Passageways
• Use a vacuum cleaner or pressurized air
to clean.
Exterior
• Use a soft cloth dampened with a mild
soap and water mixture. Wipe the cabi-
net to remove dust.