SERVICING
41
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
PREVEN
T
U
NRELIA
B
LE
O
PERA
T
I
O
N
O
R EQ
U
IPMEN
T
DAMAGE
,
TH
E
INLE
T
GAS S
U
PPL
Y
PRESS
U
RE M
U
S
T
B
E AS SPECI
F
IED
O
N
TH
E
U
NI
T
RA
T
ING PLA
T
E WI
TH
ALL
OTH
ER
HOU
SE
HO
LD GAS
F
IRED APPLIANCES
O
PERA
T
ING
.
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 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
D
ISC
O
NNEC
T
ELEC
T
RICAL P
O
WER AND S
HUT
OFF
GAS S
U
PPL
Y.
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 36G22 gas valves.
10.0
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.
WARNING
H
IG
H
V
O
L
T
AGE
D
ISC
O
NNEC
T
ALL
ELEC
T
RICAL P
O
WER AND S
HUT
OFF
GAS
S
U
PPL
Y
B
E
FO
RE SERVICING
O
R INS
T
ALLING
TH
IS
U
NI
T.
M
U
L
T
IPLE P
O
WER S
OU
RCES MA
Y
B
E PRESEN
T.
F
AIL
U
RE
TO
D
O
S
O
MA
Y
CA
U
SE PR
O
PER
TY
DAMAGE
,
PERS
O
NAL INJ
U
R
Y
O
R DEA
TH.
5. Disconnect manometer after turning off gas at manual
shutoff valve. Reinstall plug before turning on gas to
furnace.
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.
8. Turn on electrical power and verify proper unit operation.
