38
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 shuto
valve external to the furnace.
2. Turn o all electrical power to the system.
3. Outlet pressure tap connections:
White-Rodgers 36J22 valve: Back outlet pressure
test screw (inlet/outlet pressure tap) out one turn
(counterclockwise, not more than one turn).
4. Attach a hose and manometer to the outlet pressure tap
(White-Rodgers valve).
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
ring. Adjust manifold pressure using the Manifold
Gas Pressure table shown on this page.
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 o all electrical power and gas supply to the
system.
10. Remove the manometer hose from the hose barb
tting or outlet pressure tap.
11. Replace outlet pressure tap: White-Rodgers 36J22
valve: Turn outlet pressure test screw in to seal pressure
port (clockwise, 7 in-lb minimum).
12. Turn on electrical power and gas supply to the
system.
13. Close thermostat contacts “R” and “W” to energize the
valve.
Using a leak detection solution or soap suds, check for
leaks at outlet or screw (White-Rodgers valve). Bubbles
forming indicate a leak. SHUT OFF GAS AND REPAIR
ALL LEAKS IMMEDIATELY!
T
O
PREVENT
UNRELIABLE
OPERATION
OR
,
THE
INLET
SUPPLY
PRESSURE
BE
AS
ON
THE
UNIT
PLATE
ALL
OTHER
HOUSEHOLD
APPLIANCES
The actual gas input rate to the furnace must never be
greater than that specied on the unit rating plate. To
measure natural gas input using the gas meter, use the
following procedure.
1. Turn OFF the gas supply to all other gas-burning
appliances except the furnace.
2. While the furnace is operating at high re rate, time
and record one complete revolution of the gas meter
dial, measuring the smallest quantity, usually the dial
that indicates 1/2 cu. ft. per revolution. You will use
this number to calculate the quantity of gas in cubic
ft. if the furnace would consume if it ran steadily for
one hour (3600 seconds).
3. If the 1/2 cu. ft. dial was used, multiply your number
x 2.
EXAMPLE: If it took 23 seconds to complete one
revolution of the 1/2 ft. dial (23 x 2 = 46).
This tells us that at this rate, it would take 46 seconds to
consume one cu. ft. of gas. 3600 / 46 = 78.
This tells us that in one hour, the furnace would consume
78 cu. ft. of gas.
The typical value range for 1 cu. ft. of natural gas is around
1000 BTU. Check with your gas utility, if possible. In this
example, the furnace is consuming 78,000 BTUH.
+
4. Turn ON gas to and relight all other appliances
turned o in step 1. Be certain that all appliances
are functioning properly and that all pilot burners are
operating.
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