26
pressure must be measured with the burners operating. To
measure the gas supply pressure, use the following proce
-
dure.
1. Turn OFF gas to furnace at the manual gas shutoff valve
external to the furnace. Back inlet pressure test port
screw turn counter clockwise, not more than one turn.
2. Connect a calibrated water U tube manometer (or
appropriate gas pressure gauge) at either the gas
valve inlet pressure tap or the gas piping drip leg. See
White-Rodgers 36J22Y-204 gas valve figure below for
location of inlet pressure tap.
OUTLET
INLET
Gas Valve ON/OFF Selector Switch
Outlet Pressure
Inlet Pressure
Regulator
Cover Screw
White-Rodgers Model 36J22Y-204
Figure 34A
.
Regulator Cover
Screw
White-Rodgers Model 36J22Y-204
Connected to Manometer
Figure 34B
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 4, on page 21.
If supply pressure differs from table, make the necessary adjust
-
ments to pressure 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 and tighten as
needed before turning on gas to furnace.
6. Turn OFF any unnecessary gas appliances stated in
step 3.
.
Measuring Inlet Gas Pressure (Alt. Method)
Figure 35
Gas Manifold Pressure Measurement and
Adjustment
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 procedure.
1. Turn OFF gas to furnace at the manual gas shutoff valve
external to the furnace.
2. Turn off all electrical power to the system.
3. Outlet pressure tap connections:
White-Rodgers 36J22 valve: Back outlet pressure
test screw (outlet pressure tap) out one turn
(counterclockwise, not more than one turn).
4. Connect calibrated U tube manometer (or appropriate
pressure gauge) at the gas valve outlet pressure tap.
See White-Rodgers 36J22Y-204 gas valve Figure 34A
& 34B for location of outlet pressure tap.
5. Turn ON the gas supply.
6. Turn on power and close thermostat “R” and “W”
contacts to provide a call for heat.
7. Measure the gas manifold pressure with burners
firing. Adjust manifold pressure using the
Manifold
Gas Pressure
table 8 shown below.
8. Remove regulator cover screw from the outlet pressure
regulator adjust tower and turn screw clockwise to increase
pressure or counterclockwise to decrease pressure.
Replace regulator cover screw.
9. Turn off all electrical power and gas supply to the
system.
