G I R M (N G O ); As Nput Ate Easurement Atural As Nly; Circulator Blower Speeds; Emperature Ise - Goodman GMV9 Installation Instructions Manual

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.
M anifold Gas Pressure
Gas
Natural Low Stage
High Stage
Propane Low Stage
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 sum of the installation's gas heating value and 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 x 3600 sec/hr) ÷ 34 sec/ ft
Input = 106,000 BTU/hr
Minor changes to the input rate may be accomplished through mani-
fold pressure adjustments at the gas valve. Refer to Section XIV,
Startup Procedure and Adjustment - Gas Manifold Pressure Mea-
surement and Adjustment for details. NOTE: The final manifold
pressure cannot vary by more than ± 0.3" w.c. from the specified
setting. Consult your local gas supplier if additional input rate ad-
justment is required.
5. Repeat steps 2 through 4 on high stage.
6. 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.
T R
EMPERATURE ISE
Temperature rise must be within the range specified on the unit rat-
ing 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 Product Data Book 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
Range Nom inal
1.6 - 2.2" w .c. 1.9" w .c.
3.2 - 3.8" w .c. 3.5" w .c.
5.7 - 6.3" w .c. 6.0" w .c.
9.7 - 10.3" w .c. 10.0" w .c.
(N G O
ATURAL AS NLY
3
3
3
exchanger.
RADIATION "LINE OF SIG HT"
)
Temperature Rise Measurement
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
3 ) of
to Section XIV, Startup Procedure and Adjustment -Circulator
Blower Speeds for speed changing details.
C B
IRCULATOR LOWER
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 multi-speed circulator blower. 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.), for the proper selection of heating and cooling speeds. The
heating blower speed is shipped set at "B", and the cooling blower
speed is set at "D". These blower speeds should be adjusted by the
installer to match the installation requirements so as to provide the
correct heating temperature rise and correct cooling CFM.
Use the CFM LED (green), adjacent to the integrated control
module fuse to verify airflow quantity. The green CFM LED
blinks once for each 100 CFM of airflow.
1. Determine the tonnage of the cooling system installed with
the furnace. If the cooling capacity is in BTU/hr divide it by
12,000 to convert capacity to TONs.
Example: Cooling Capacity of 30,000 BTU/hr.
30,000/12,000 = 2.5 Tons
2. Determine the proper air flow for the cooling system. Most
cooling systems are designed to work with air flows between
350 and 450 CFM per ton. Most manufacturers recommend
an air flow of about 400 CFM per ton.
Example: 2.5 tons X 400 CFM per ton = 1000 CFM
The cooling system manufacturer's instructions must be checked
for required air flow. Any electronic air cleaners or other devices
may require specific air flows, consult installation instructions of those
devices for requirements.
3. Knowing the furnace model, locate the high stage cooling air
flow charts in the Product Data Book applicable to your
model*. Look up the cooling air flow determined in step 2
and find the required cooling speed and adjustment setting.
Example:
29
HEAT EXCHANGER
SUPPLY
T T
RISE =
-
S UP PLY RE TURN
T
RE TUR N
RETURN
AIR
S
PEEDS
WARNING
A *MV90704BXA furnace installed with a 2.5
ton air conditioning system. The air flow needed
is 1000 CFM. Looking at the cooling speed
AIR
T
SU PP LY