Inspecting Heater; Burner Flame Pattern - Desa NZ108 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. All
burners will turn off and on.
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.
OPERATING
bLOWER
This heater has a thermostatic blower that will
automatically turn ON or OFF.
Note: Your heater and thermostat blower will
not turn on and off at the same time. The
heater may run for several minutes before the
blower turns on. After the heater modulates to
the pilot position, the blower will continue to
run. The blower will shut off after the heater
cabinet temperature decreases.
Note: It is safe to operate heater with blower
turned off. However, the blower helps distrib-
ute heated air from the heater.
16

INSpECTING HEATER

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 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 4
• turn heater off (see To Turn Off Gas to Ap-
pliance, page 15)
• see Troubleshooting, page 18
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
Figure 23 - Correct Pilot Flame Pattern
Thermocouple
Figure 24 - Incorrect Pilot Flame Pattern

BURNER FLAME PATTERN

Figure 25 shows a correct burner flame pat-
tern. Figure 6 shows an incorrect burner
flame pattern.
If burner flame pattern is incorrect, as shown
in Figure 6
• turn heater off (see To Turn Off Gas to Ap-
pliance, page 15)
• see Troubleshooting, page 18
Figure 25 - Correct
Burner Flame
www.desatech.com
Blue Flame
Yellow Flame
Figure 26 - Incorrect
Pattern
Pilot Burner
Pilot Burner
Burner Flame
Pattern
119171-01E