
33
WARNING
Disconnect ALL Gas and Electric Power Supply.
1. Check orifice visually for distortion and/or burrs.
2. Check orifice size with orifice sizing drills.
A
GAS
STREAM B
The length of Dimension “A” determines the angle of Gas
Stream “B”.
DENT OR
BURR
GAS
STREAM B
A dent or burr will cause a severe deflection of the gas
stream.
S-307 Checking Gas Pressure
Gas Supply Pressure Measurement
CAUTION
To 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
measured 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
Disconnect electrical power and shut off gas supply.
1. After turning off gas to furnace at the manual gas
shutoff valve external to the furnace, remove burner
compartment door to gain access to the gas valve.
2. Connect a calibrated water manometer (or appropriate
gas pressure gauge) at either the gas valve inlet
pressure tap or the gas piping drip leg as shown in the
following figures.
NOTE: At either location, a hose fitting must be
installed prior to making the hose connection.
NOTE: Use adapter kit #0151K00000S to measure
gas pressure on White-Rodgers and 36[G/J]54 gas
valves.
GAS LINE
GAS SHUTOFF VALVE
GAS LINE
TO FURNACE
DRIP LEG CAP
WITH FITTING
MANOMETER HOSE
MANOMETER
OPEN TO
ATMOSPHERE
Measuring Inlet Gas Pressure
(Alternate Method)
3. Turn ON the gas and electrical power supply and
operate the furnace and all other gas consuming
appliances on the same gas supply line.
4. Measure furnace gas supply pressure with burners
firing. Supply pressure must be within the range
specified in the following table.
Natural Gas
Minimum: 4.5" w.c.
Maximum: 10.0" w.c.
Propane Gas Minimum: 11.0" w.c. Maximum: 13.0" w.c.
INLET GAS SUPPLY PRESSURE
If supply pressure differs from above, make necessary
adjustments to pressure regulator, gas piping size, etc.,
and/or consult with local gas utility.
SERVICING