Amana M9C96 Series Manual page 33

Gas Input Rate Measurement (Natural Gas
Only)
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 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.
Temperature Rise
Temperature rise must be within the range specified on the
unit rating plate. An incorrect temperature rise may result
in condensing in or overheating of the heat exchanger. An
airflow and temperature rise table is provided in the Specifi-
cation 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.
Maximum: 10.0" w.c.
Maximum: 13.0" w.c.
Blower Heat Off Delay Timings
The integrated control module provides a selectable heat off
delay function. The heat off delay period may be set to 90,
120, 150, 180 seconds. The delay is factory shipped at 150
seconds but may be changed to suit the installation require-
ments and/or homeowner preference.
33
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.
Temperature Rise Measurement
T
O AVOID PERSONAL INJURY OR DEATH DUE TO ELECTRICAL SHOCK
OFF
TURN POWER TO THE FURNACE BEFORE CHANGING SPEED TAPS
SUPPLY
AIR
RETURN
AIR
Figure 45
WARNING
,
.