Desa WMN20A - Manual (Page 17)

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oPeRaTIoN
Continued
BURNER 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.
Figure 26 shows a correct burner flame pattern.
Figure 27 shows an incorrect burner flame pat-
tern. The incorrect burner flame pattern shows
yellow tipping of the flame. It also shows the
flame higher than 1/2 the glass panel height.
If burner flame pattern is incorrect, as shown
in Figure 27
• turn heater off (see To Turn Off Gas To
Appliance, page 16)
• see Troubleshooting, page 19
INsPeCTING HeaTeR
Figure 25 - Incorrect Pilot Flame Pattern
Figure 24 - Correct Pilot Flame Pattern
Figure 26 - Correct Burner Flame Pattern
Yellow
Tipping
Figure 27 - Incorrect Burner Flame Pattern
1 /
2
Glass
Height
1 /
2
Glass
Height
Blue
Flame
Check pilot flame pattern and burner flame
pattern often.
PILOT FLAME PATTERN
Figure 24 shows a correct pilot flame pattern.
Figure 25 shows an incorrect pilot flame pat-
tern. The incorrect pilot flame is not touching
the thermocouple. This will cause the thermo-
couple to cool. When the thermocouple cools,
the heater will shut down.
If pilot flame pattern is incorrect, as shown
in Figure 25
• turn heater off (see To Turn Off Gas to Ap-
pliance, page 16)
• see Troubleshooting, page 19
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.
Thermocouple
Pilot Burner
Pilot Burner
Thermocouple
Blue Flame
Yellow Flame
Extension Cord
Use extension cord if needed. The cord must
have a three-prong, grounding plug and a
three-hole receptacle. Make sure cord is in
good shape. It must be heavy enough to carry
the current needed. An undersized cord will
cause a drop in line voltage. This will result in
loss of power and overheating. Use a No. 16
AWG cord for lengths less than 50 feet.
CAUTION: Verify proper op-
eration after servicing.
Operating Blower
The blower is connected to a thermostat. When
unit heats up, the blower will operate. A few
Figure 23 - Wiring Diagram For Blower
Accessory
Thermostat
Sensor
Switch
Green
White
Green
White
110/115
V.A.C.
Blower
Motor
Black
Black
minutes after unit cycles off or is turned off,
blower will shut off. Blower will cycle on and off
in this manner. Note: If you have a heater with
a thermostat, the heater and blower will not turn
off and on at exactly the same time. Blower cycle
times will vary with heat setting selected.