Table of Contents
Advertisement
SERVICING
D
ALL
ISCONNECT
POWER BEFORE SERVICING
CHECKING MAIN BURNERS
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, orifice sizing, gas pressure, primary and
secondary air, vent and proper seating of burners.
BURNERS
Burners have been redesigned for 34.5" chassis furnaces.
Overall length and width dimensions remain the same as 40"
model burners. The burners used 34.5" models have burner
head insert with larger diameter center hole and a larger
number of surrounding holes.
D
ALL G
ISCONNECT
AS AND
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.
CHECKING ORIFICES
A/GMVM, A/GCVM model furnaces have factory installed #45
natural gas orifices.
The only time resizing is required is when a reduction in firing
rate is required for an increase in altitude or a funace is being
converted for use with L.P. gas.
WARNING
34.5 Burners
WARNING
E
P
S
LECTRICAL
OWER
UPPLY.
Orifices should be treated with care in order to prevent dam-
age. They should be removed and installed with a box-end
wrench in order to prevent distortion. In no instance should
an orifice be peened over and re-drilled. This will change
the angle or deflection of the vacuum effect or entraining
of primary air, which will make it difficult to adjust the flame
properly. This same problem can occur if an orifice spud of a
different length is substituted.
D
ALL G
ISCONNECT
AS AND
1. Check orifice visually for distortion and/or burrs.
2. Check orifice size by the number stamped on the orifice.
The length of Dimension "A" determines the angle of Gas
Stream "B".
A dent or burr will cause a severe deflection of the gas stream.
CHECKING GAS PRESSURE
GAS SUPPLY PRESSURE MEASUREMENT
T
O PREVENT UNRELIABLE OPERATION OR EQUIPMENT DAMAGE, THE
INLET GAS SUPPLY PRESSURE MUST BE AS SPECIFIED ON THE UNIT
RATING PLATE WITH ALL OTHER HOUSEHOLD GAS FIRED APPLIANCES
OPERATING.
Gas inlet and manifold pressures should be checked and
adjusted in accordance to the type of fuel being consumed.
The line pressure supplied to the gas valve must be within
the range specified below. The supply pressure can be mea-
sured at the gas valve inlet pressure tap or at a hose fitting
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.
WARNING
E
P
S
LECTRICAL
OWER
UPPLY.
A
GAS
STREAM B
DENT OR
BURR
GAS
STREAM B
CAUTION
63
Advertisement
Table of Contents
