Service Manual

SERVICING
81
installed.
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
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.
CAUTION
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
D
ISCONNECT 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 compart-
ment 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 pres-
sure tap or the gas piping drip leg as shown in the fol-
lowing figures. Refer to Measuring Gas Pressure: Single
Stage Valves figure for single stage valve inlet pressure
tap connections. Refer to Measuring Gas Pressure:
Two-Stage Valves figure for two-stage gas valve inlet
pressure tap connections.
NOTE: At either location, a hose fitting must be installed
prior to making the hose connection.
NOTE: Use adapter kit #0151K00000S to measure gas pres-
sure on White-Rodgers 36G22 and 36G54 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 oper-
ate the furnace and all other gas consuming appliances
on the same gas supply line.
4. Measure furnace gas supply pressure with burners fir-
ing. 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 ad-
justments to pressure regulator, gas piping size, etc., and/
or consult with local gas utility.
WARNING
HIGH VOLTAGE
D
ISCONNECT
ALL
ELECTRICAL POWER AND SHUT OFF GAS
SUPPLY BEFORE SERVICING OR INSTALLING THIS UNIT.
MULTIPLE POWER SOURCES MAY BE PRESENT. FAILURE TO
DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
5. Disconnect manometer after turning off gas at manual
shutoff valve. Reinstall plug before turning on gas to fur-
nace.
6. Turn OFF any unnecessary gas appliances started in
step 3.
7. Turn on gas to furnace and check for leaks. If leaks are
found, repair and then reinstall burner compartment door.