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O
F
F
O
F
F
87 4321
O
F
F
O
N
4321
O
N
O
F
F
4321
O
N
O
N
4321
Cooling
Speed
Tap A
Cooling
Speed
Tap B
Cooling
Speed
Tap C
Cooling
Speed
Tap D
*
Cooling Speed Taps
(
* indicates factory setting)
O
F
F
O
F
F
87 4321
O
F
F
O
N
87 4321
O
N
O
F
F
87 4321
O
N
O
N
87 4321
Heating
Speed
Tap A
Heating
Speed
Tap B
Heating
Speed
Tap C
Heating
Speed
Tap D
Heating Speed Taps
(
* indicates factory setting)
*
O
F
F
O
F
F
4321
O
F
F
O
N
4321
O
N
O
F
F
4321
Normal
+ (Plus)
Adjust
- (Minus)
Adjust
Adjust Taps
(
*
indicates factory setting)
*
87
87
87
87
87
87
65
65
65
65
65
65
65
65
65
65
65
5. The multi-speed circulator blower also offers several
custom ON/OFF ramping profiles. These profiles may be
used to enhance cooling performance and increase comfort
level. The ramping profiles are selected using DIP switches
5 and 6. Refer to the following figure for switch positions
and their corresponding taps. Refer to the bullet points
below for a description of each ramping profile. Turn OFF
power to the furnace for a minimum of 10 seconds, allowing
motor to reset and recognize the new profile selection. Turn
ON power to the furnace. Verify profile selection by counting
the green CFM LED blinks and timing each step of the
ramping profile.
• Profile A provides only an OFF delay of one (1) minute at
100% of the cooling demand airflow.
OFF
100% CFM
Cooling
Demand
100% CFM
1 min
OFF
• Profile B ramps up to full cooling demand airflow by first
stepping up to 50% of the full demand for 30 seconds. The
motor then ramps to 100% of the required airflow. A one (1)
minute OFF delay at 100% of the cooling airflow.
100% CFM 100% CFM
1 min
Cooling Demand
50% CFM
1/2 min
OFF OFF
• Profile C ramps up to 82% of the full cooling demand airflow
and operates there for approximately 7 1/2 minutes. The
motor then steps up to the full demand airflow. Profile C
also has a one (1) minute 100% OFF delay.
OFF
1 min
100% CFM100% CFM82% CFM
7 1/2 min
Cooling Demand
• Profile D ramps up to 50% of the demand for 1/2 minute,
then ramps to 82% of the full cooling demand airflow and
operates there for approximately 7 1/2 minutes. The motor
then steps up to the full demand airflow. Profile D has a 1/
2 minute at 50% airflow OFF delay.
82% CFM
7 1/2 min
100% CFM 50% CFM
1/2 min
1/2 min
50% CFMOFF OFF
Cooling Demand
O
F
F
O
F
F
87 4321
O
F
F
O
N
4321
4321
4321
Ramping
Profile
Tap A
Ramping
Profile
Tap B
Ramping
Profile
Tap C
Ramping
Profile
Tap D
*
Ramping Profiles
(
* indicates factory setting)
87
87
87
65
65
65
65
O
N
O
F
F
O
N
O
N
6. Select the heating speed from the heating speed chart in
the Product Data Book applicable to your model* for your
model. The adjust setting (already established by the
cooling speed selection) determines which set of speeds
are available. The selected speed must provide a
temperature rise within the rise range listed with the
particular model.
Example: The *MV90704BXA is set for 990 CFM on
cooling, the “ADJUST” is set to “-” (minus).
The four heating speeds available are “A
Minus”, “B Minus”, “C Minus”, and “D Minus”.
“A Minus” has a rise of 56°F for both stages
which is within the 30-60°F rise range for the
*MV90704BXA. This setting will keep electrical
consumption to a minimum. Set the “Heat”
speed DIP switches to “A”.
7. Select the desired “heating” speed tap by positioning
switches 7 and 8 appropriately. Refer to figure above. Turn
off power to furnace for a minimum of 10 seconds, allowing