Temperature Rise; Circulator Blower Speeds - Goodman *MVM96 Installation Instructions Manual

number of seconds per cubic foot. The measured input
must not be greater than the input indicated on the unit
rating plate.
EXAMPLE:
Heating value of natural gas supplied, typically 1,000
BTUH CU FT: (exact heating value may be obtained
from your gas provider)
3
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
Input = (1,000 BTU/ft 3
Input = 106,000 BTU/hr
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.
5. 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 rating plate. An incorrect temperature rise may result in
condensing in or overheating of the heat exchanger. An air-
flow and temperature rise table is provided in the Specification
Sheet applicable to your model. Determine and adjust tem-
perature 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.
Tempera ture Rise Range (°)
A/GMVM960603BX
A/GMVM960805CX
A/GMVM961005DX
A/GMVM961155DX
A/GCVM960604 CX
A/GCVM960805 DX
A/GCVM961005 DX
3
x 3600 sec/hr) ÷ 34 sec/ ft
20 - 50
35 - 65
35 - 65
35 - 65
20 - 50
20 - 50
25 - 55
3
C
IRCULATOR
T
O AVOID PERSONAL
OFF
TURN
This furnace is equipped with an ECM circulator blower. The
heating blower speed is shipped set at "B", and the cooling blower
speed setting is "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 dual 7-segment LED display adjacent to the DIP switches
to obtain the approximate airflow quantity. The airflow quantity is
displayed as a number on the display, rounded to the nearest 100
CFM. The display alternates airflow delivery indication and the
operating mode indication.
Example: The airflow being delivered is 1225 CFM. The display
indicates 12. If the airflow being delivered is 1275, the display
indicates 13.
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.
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
41
Temperature Rise Measurement
B S
LOWER PEEDS
WARNING
INJURY OR DEATH DUE
POWER TO THE FURNACE BEFORE
30,000/12,000 = 2.5 Tons
SUPPLY
AIR
RETURN
AIR
,
TO ELECTRICAL SHOCK
.
CHANGING SPEED TAPS