Gas Input Rate Measurement (Natural Gas Only ); Temperature Rise; Circulator Blower Speed Adjustment - Amana AMH8 Installation Instructions Manual

Gas-fired warm air furnace
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13. Turn outlet pressure test screw in to seal pressure port
(clockwise, 7 in-lb minimum).
14. Turn on electrical power and gas supply to the system.
15. Turn on system power and energize valve.
16. Using a leak detection solution or soap suds, check for
leaks at pressure boss screw. Bubbles forming indicate a
leak. SHUT OFF GAS AND FIX ALL LEAKS IMMEDIATELY.
NOTE: For gas to gas conversion, consult your dealer for
appropriate conversion.
Manifold Gas Pressure
Gas
Rate
Low Stage
Natural
High Stage
Low Stage
Propane
High Stage
G
I
R
M
AS
NPUT
ATE
EASUREMENT
The 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, time and record one
complete revolution of the smallest gas meter dial.
3. Calculate the number of seconds per cubic foot (sec/ ft
gas being delivered to the furnace. If the dial is a one cubic
foot dial, divide the number of seconds recorded in step 2
by one. If the dial is a two cubic foot dial, divide the number
of seconds recorded in step 2 by two.
4. Calculate the furnace input in BTUs per hour (BTU/ hr).
Input equals the installation's gas heating value multiplied
by a conversion factor (hours to seconds), divided by the
number of seconds per cubic foot. The measured input
must not be greater than the input indicated on the unit
rating plate.
EXAMPLE:
Installation's gas heating (HTG) value: 1,000 BTU/ft
(Obtained from gas supplier)
Installation's seconds per cubic foot: 34 sec/ ft
Conversion Factor (hours to seconds): 3600 sec/hr
Input = (Htg. value x 3600) ÷ seconds per cubic foot
3
Input = (1,000 BTU/ft
Input = 106,000 BTU/hr
This measured input must not be greater than the input
indicated on the unit rating plate.
5. Turn ON gas and relight appliances turned off in step 1.
Ensure all the appliances are functioning properly and that
all pilot burners are operating.
T
R
EMPERATURE
ISE
Air temperature rise is the temperature difference between supply
and return air. The proper amount of temperature rise is usually
obtained when the unit is operated at the rated input with the "as
shipped" blower speed. If the correct amount of temperature rise
is not obtained, it may be necessary to change the blower speed.
Range
Nominal
1.7 to 2.3" w.c.
2.0" w.c.
3.2 to 3.8" w.c.
3.5" w.c.
5.7 to 6.3" w.c.
6.0" w.c.
9.7 to 10.3" w.c. 10.0" w.c.
(N
G
O
ATURAL
AS
3
3
x 3600 sec/hr) ÷ 34 sec/ ft
An incorrect temperature rise can cause condensing in or
overheating of the heat exchanger. Determine and adjust the
temperature rise as follows. The temperature rise must be within
the range specified on the rating plate or Product Data Book
applicable to your model. (Please contact your distributor or our
website for the applicable product data book referred to in this
manual.)
)
NLY
1. Operate furnace with burners firing approximately 15
minutes. Ensure all registers are open and all duct
dampers are in their final (fully or partially open) position.
3
) of
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 the following section for speed changing details.
C
IRCULATOR
3
T
O AVOID PERSONAL INJURY OR DEATH DUE TO ELECTRICAL SHOCK, TURN
OFF
POWER TO THE FURNACE BEFORE CHANGING SPEED TAPS.
This furnace is equipped with a PSC circulator blower motor. This
blower provides ease in adjusting blower speeds. The Product
Data Book applicable to your model provides an airflow table
showing the relationship between airflow (CFM) and external static
pressure (E.S.P.) and a table for the proper selection of heating
and cooling speeds. The cooling blower speed is shipped set on
HIGH. High heat ships on MEDIUM and low heat is shipped on
MEDIUM-LO. These blower speeds should be adjusted by the
installer to match the installation requirements so as to provide
the correct heating temperature rise and the correct cooling CFM.
To adjust the circulator blower speed, proceed as follows:
24
HEAT EXCHANGER
RADIATION "LINE OF SIGHT"
T
RISE =
SUPPLY
Temperature Rise Measurement
B
S
A
LOWER
PEED
DJUSTMENT
WARNING
SUPPLY
AIR
T
SUPPLY
T
-
RETURN
T
RETURN
RETURN
AIR

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