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Removing Main Burner
1. Disconnect the thermopile and pilot supply line at the pilot burner.
2. Remove the burner compartment cover.
3. Remove orifice shield.
4. Remove bolt on each side of burner and lift out.
Cleaning Main Burner
The main burner may be cleaned by forcing water into the ports and the
throat of the burner. The main burner should be blown dry or heated to
remove water from main burner.
Removing Main Burner Orifice
1. Open the brass union located after the gas valve.
2. Loosen valve bracket.
3. Remove the 3/8" (10mm)manifold pipe that is attached to the union
elbow until the manifold pipe is free.
4. The main burner orifice is at the end of the manifold pipe.
Removing 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.
Cleaning Pilot Orifice
After use, cleaning of the pilot burner may be required for the proper
flame. Also, cleaning of the pilot burner may be required due to spiders
(spider webs). 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.
Cleaning Combustion Chamber
When the main burner and vent cap are removed, all internal areas of the
combustion chamber are accessible for cleaning with a vacuum hose.
Proper Pilot Flame (Figure 6)
The correct flame will be almost horizontal, blue and will extend past the
thermopile 1/4" (6mm). The flame will surround the thermopile just
below the tip.
On propane (LP-gas) slight yellow might occur where the pilot flame and
burner flame meet.
Natural gas pilots require adjusting when the inlet pressure is above 5"
w.c. (1.25kPa) Turn adjustment screw clockwise to reduce flame.
Propane (LP-gas) will not require adjusting.
Proper Main Burner Flame (Figure 7)
There will be a short blue inner flame with a much larger lighter blue
secondary flame. The burner flame may have a yellow tip when hot. See
the burner drawing showing the approximate heights of each part of the
flame. 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. After
use, cleaning may be required for the proper flame.
R-2070
Figure 6
BURNER FLAME
PRIMARY FLAME 1/4" (6mm) TO 1/2" (13mm)
SECONDARY FLAME 4" (102mm) TO 6" (152mm)
Thermostat Location
Millivolt wall thermostats are specially designed for use on self-generating
systems. They should never be used on line or low voltage A.C. circuits.
Interior Wall — The thermostat should be installed on an inside wall
away from the furnace but in the same room.
Note: Use 16 gauge wire to prevent excessive loss of millivolts.
Proper operation depends on a good pilot flame. The flame must cover
the top of the thermopile. Cleaning of the pilot orifice and burner may be
required due to spiders.
System Check (Figure 8)
A millivolt meter is required to check the system. Millivolt readings
should be:
• Across the thermopile terminals, 400-450 millivolts with thermostat
OFF.
• Across the thermopile terminals, 150-250 millivolts with thermostat
ON.
• Across the thermostat wires at the valve, less than 30 millivolts with
thermostat ON.
• Across the thermostat wires at the thermostat, less than 5 millivolts
with thermostat ON. (Strong winds, dirty pilot and low pressure will
reduce readings.)
Figure 7
Figure 8
Page 7
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