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Atmosphere
Outlet
Pressure Boss
Inlet
Pressure
Boss
White-Rodgers Model 36J54 Connected to Manometer
G
I
R
M
AS
NPUT
ATE
EASUREMENT
INLET GAS SUPPLY PRESSURE
Natural Gas
Minimum: 4.5" w.c.
Propane Gas
Minimum: 11.0" w.c.
The actual gas input rate to the furnace must never be greater
than that specified 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 fire 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.
NOTE: The final manifold pressure cannot vary by more
than ± 0.3" w.c. for Natural and + 0.5" for LP from
High Fire Regulator
Adjust
Regulator
Low Fire
Regulator
Adjust
Common
Terminal(C)
Figure 39B
(N
G
O
ATURAL
AS
NLY
Maximum: 10.0" w.c.
Maximum: 13.0" w.c.
the specified setting. Consult your local gas supplier if
additional input rate adjustment is required.
4. Turn ON gas to and relight all other appliances turned off
in step 1. Be certain that all appliances are functioning
properly and that all pilot burners are operating.
Vent
T
EMPERATURE
Temperature rise must be within the range specified on the unit
rating plate. An incorrect temperature rise may result in con-
densing in or overheating of the heat exchanger. An airflow and
temperature rise table is provided in the Specification Sheet
applicable to your model. Determine and adjust temperature
rise as follows:
1. Operate furnace with burners firing for approximately ten
minutes. Ensure all registers are open and all duct dampers
are in their final (fully or partially open) position.
2. Place thermometers in the return and supply ducts as close
to the furnace as possible. Thermometers must not be
influenced by radiant heat by being able to "see" the heat
exchanger.
3. Subtract the return air temperature from the supply air
temperature to determine the air temperature rise. Allow
)
adequate time for thermometer readings to stabilize.
4. Adjust temperature rise by adjusting the circulator blower
speed. Increase blower speed to reduce temperature rise.
Decrease blower speed to increase temperature rise. Refer
to Startup Procedure and Adjustment -Circulator Blower
Speeds for speed changing details.
C
IRCULATOR
This furnace is equipped with a multi-speed ECM motor. The
line voltage (115 VAC) power supply to the motor is constant
48
R
ISE
Temperature Rise Measurement
Figure 40
B
S
LOWER
PEEDS
SUPPLY
AIR
RETURN
AIR
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