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Temperature Rise Measurement
Rise = Supply air temperature - Return air temperature
A
A. Heat exchanger radiation
"line of sight"
B. Supply air
4. Subtract the return air temperature from the supply air
temperature to determine the air temperature rise. Allow
adequate time for thermometer readings to stabilize.
5. Adjust the temperature rise by adjusting the circulator blower
speed. Increase blower speed to reduce temperature rise.
Decrease blower speed to increase temperature rise. Refer to
"Circulator Blower Speeds" for speed changing details.
Circulator Blower Speeds
WARNING
Goodman 117
To 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 multispeed circulator blower. This
blower provides ease in adjusting blower speeds. The
Specification Sheet 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 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 1,225 CFM. The
display indicates 12. If the airflow being delivered is 1,275,
the display indicates 13.
1. Determine the tonnage of the cooling system installed with
the furnace. If the cooling capacity is in Btu/h, divide it by
12,000 to convert capacity to Tons.
Example: Cooling Capacity of 30,000 Btu/h
30,000/12,000 = 2.5 Tons
B
C
D
E
C. Supply air temperature
D. Return air temperature
E. Return air
2. Determine the proper airflow for the cooling system. Most
cooling systems are designed to work with airflows between
350 and 450 CFM per ton. Most manufacturers recommend
an airflow of about 400 CFM per ton.
Example: 2.5 tons X 400 CFM per ton = 1,000 CFM
NOTE: The cooling system manufacturer's instructions must be
checked for required airflow. Any electronic air cleaners or other
devices may require specific airflows, consult installation
instructions of those devices for requirements.
3. Knowing the furnace model, locate the high-stage cooling
airflow charts in the Specification Sheet applicable to your
model. Look up the cooling airflow determined in Step 2 and
find the required cooling speed and adjustment setting.
Example: A WGFM28070V4BX furnace installed with a
2.5 ton air conditioning system. The airflow needed is
1,000 CFM. Looking at the cooling speed chart for
WGFM28070V4BX, find the airflow closest to 1,000 CFM. A
cooling airflow of 990 CFM can be attained by setting the
cooling speed to C and the adjustment to "-" (minus).
4. Continuous fan speed is 30% of the furnace's maximum
airflow capability.
Example: If the furnace's maximum airflow capability is
2,000 CFM, the continuous fan speed will be
0.30 x 2,000 CFM = 600 CFM.
5. Locate the blower speed selection DIP switches on the
integrated control module. Select the desired cooling speed
tap by positioning DIP switches 1 and 2 appropriately.
Select the desired adjust tap by positioning DIP switches
3 and 4 appropriately. Refer to the following charts for DIP
switch positions and their corresponding taps. Verify CFM by
noting the number displayed on the dual 7-segment LED
display.
Speed Selection DIP Switches
Cool
Adjust
Selection
Selection
Switches
Switches
Tap
1
2
3
A
Off
Off
Off
B
On
Off
On
C
Off
On
Off
D
On
On
On
Switch Bank: S3
DIP Switch Number
Cooling Tap
1
A
Off
B
On
C
Off
D*
On
*Indicates factory setting
Profile
Heat
Selection
Selection
Switches
Switches
4
5
6
7
Off
Off
Off
Off
Off
On
Off
On
On
Off
On
Off
On
On
On
On
2
Off
Off
On
On
8
Off
Off
On
On
25
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