Monessen Hearth PL20 User Manual

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90D0093
1
Parlor Vent Free Fireplace
FP2273
pilot bad flame
FP2272
pilot correct flame
FLAME APPEARANCE
Flames from the pilot, front and rear burner should be visually checked as soon as the 
heater is installed.
 In addition, periodically check the flames visually during operation.
CHECk THE PILOT FLAME
The pilot flame must always be present when the heater is in operation. It should just 
touch the top of the thermocouple tip for natural. Refer to Figure 23 for correct pilot flame. 
If the pilot flame does not touch the thermocouple, then the main burner cannot function 
reliably. Refer to Figure 23 for incorrect shape of pilot flame.
Figure 23 - 
Millivolt Control Pilot Flame Appearance
Thermocouple 
for Natural Gas
Thermocouple 
for LP
FP7
Thermocouple 
for Natural Gas
Thermocouple 
for LP
FP73
MILLIVOLT CONTROL
Correct Pilot Flame Appearance
Incorrect Pilot Flame Appearance
CHECk BURNER FLAME APPEARANCE
In  normal  operation,  at  full  rate  after  15 
minutes, the flames should appear as shown 
in Figure 24.
The flames should be yellow and extend 3-4" 
above the log top surfaces. The yellow flames 
should not impinge on the logs.
LG723
PL20 log flames
Figure 24 - 
Correct Burner Flame Appearance
LG73