Desa CDL3924PT - Manual (Page 20)

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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 [Manually-Controlled Models] or page
20 [Thermostatically-Controlled Models])
• 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.
Figure 27 - Correct Pilot Flame Pattern
(Your pilot may vary from pilots shown)
Pilot Burner
Thermocouple
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.