GC9C96 Service Manual
SERVICING
28
The main burners are used to provide complete combustion
of various fuels in a limited space, and transfer this heat of
the burning process to the heat exchanger.
Proper ignition, combustion, and extinction are primarily due
to burner design, orice sizing, gas pressure, primary and
secondary air, vent and proper seating of burners.
T
G
TR
R
In checking main burners, look for signs of rust, oversized and
undersized carry over ports restricted with foreign material,
etc, burner cross-over slots should not be altered in size.
*M9C96/*C9C96 model furnaces have factory installed #45
natural gas orices (except *M9C960303AN which has #50).
The only time resizing is required is when a reduction in ring
rate is required for an increase in altitude or a furnace is being
converted for use with LP gas.
Orices should be treated with care in order to prevent
damage. They should be removed and installed with a box-
end wrench in order to prevent distortion. In no instance
should an orice be peened over and redrilled. This will
change the angle or deflection of the vacuum effect or
entraining of primary air, which will make it dicult to adjust
the ame properly. This same problem can occur if an orice
spud of a dierent length is substituted.
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1. Check orice visually for distortion and/or burrs.
2. Check orice size with orice sizing drills.
B
The length of Dimension “A” determines the angle of Gas
Stream “B”.
B
A dent or burr will cause a severe deection of the gas stream.
The line pressure supplied to the gas valve must be within the
range specied below. The supply pressure can be measured
at the gas valve inlet pressure tap or at a hose tting installed
in the gas piping drip leg. The supply pressure must be
measured with the burners operating. To measure the gas
supply pressure, use the following procedure.
INLET
OUTLET
Gas Valve On/Off
Selector Switch