34
Gas Line
Gas
Shutoff
Valve
Gas Line
To Furnace
Drip Leg Cap
With Fitting
Manometer Hose
Manometer
Open To
Atmosphere
Measuring Inlet Gas Pressure (Alt. Method)
Figure 41
G
AS
S
UPPLY
P
RESSURE
M
EASUREMENT
G
AS
P
RESSURE
T
EST
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.
1. Turn OFF gas to furnace at the manual gas shutoff valve
external to the furnace.
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. See White-Rodgers 36J22 gas valve
figure for location of inlet pressure tap.
NOTE:
If measuring gas pressure at the drip leg, a field-supplied hose barb fitting must be installed prior to making the hose
connection. If using the inlet pressure tap on the White-Rodgers 36J22 gas valve, then use the 36G/J Valve Pressure Check Kit, Part
No. 0151K00000S.
3. Turn ON the gas 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
Inlet Gas Supply Pressure
table.
If supply pressure differs from table, make the necessary adjustments to pres-
sure regulator, gas piping size, etc., and/or consult with local gas utility.
5. Turn OFF gas to furnace at the manual shutoff valve and disconnect manometer. Reinstall plug before turning on gas to
furnace.
6. Turn OFF any unnecessary gas appliances stated in step 3.
G
AS
M
ANIFOLD
P
RESSURE
M
EASUREMENT
AND
A
DJUSTMENT
Only small variations in gas pressure should be made by adjusting the gas valve
pressure regulator. The manifold pressure must be measured with the burners
operating. To measure and adjust the manifold pressure, use the following proce-
dure.
OUTLET
INLET
Gas Valve ON/OFF Selector Switch
Outlet Pressure
Inlet Pressure
Regulator
Cover Screw
White-Rodgers Model 36J22
Figure 40A
OUTLET
INLET
White-Rodgers Model 36J22
Connected to Manometer
Figure 40B
Gas
Range
Nominal
Natural
3.2 - 3.8" w.c.
3.5" w.c.
Propane
9.7 - 10.3" w.c.
10.0" w.c.
Manifold Gas Pressure
