Pilot Flame Characteristics; Main Burner Flame Characteristics - Empire Heating Systems RH-25-6 Owner's Manual

The correct flame will be almost horizontal, blue and will extend
past the thermocouple 1/4" (6mm). The flame will surround the
thermocouple just below the tip.
On Propane (LP-gas) slight yellow might occur where the pilot
flame and the burner flame meet.
Natural gas pilots require adjusting when the inlet pressure is above
5" w.c. (1.25kPa) Remove pilot adjustment cover. Turn adjustment
screw clockwise to reduce flame.
Propane (LP-gas) will not require adjusting.
After use, cleaning of the pilot burner may be required for the proper
flame. The pilot orifice can be cleaned with high pressure air or
by placing under running water. Pilot orifice must be dry before
replacement. Use a pipe cleaner to clean inside the pilot after the
pilot orifice has been removed.
To Remove Pilot Orifice
1. Disconnect the pilot supply line at the pilot burner.
2. Remove pilot orifice from pilot burner.It may be necessary to
tap on pilot burner in order to remove the pilot orifice.

MAIN BURNER FLAME CHARACTERISTICS

There will be a short blue inner flame with a larger, lighter blue
secondary flame. The burner flame may have yellow tips when hot.
Dust in the combustion air will produce an orange or red flame. Do
not mistake the orange or red flame for an improper yellow flame.
Attention: On Propane gas, if a whistling noise (resonation) occurs
close the air shutter on the main burner in order to reduce the amount
of primary air. The reduction in primary air will soften the main burner
flame and will eliminate the whistling noise (resonation).
On Propane or Natural gas if a yellow flame occurs open the air
shutter on the main burner in order to increase the amount of primary
air. The increase in primary air will sharpen the main burner and
will eliminate the yellow flame.
After use, cleaning of the main burner may be required for the proper
flame. The main burner may be cleaned by forcing water into the
ports and the throat of the burner. The burner should be blown dry
or heated to remove all water before replacement.
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PILOT FLAME CHARACTERISTICS

On Propane Gas, if a whistling noise (resonation) occurs
a. Close the air shutter on the main burner in order to reduce
the amount of primary air.
Figure 5
Figure 6
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