31
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 mod-
ule 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:
A *MV90704BXA furnace installed with a 2.5
ton air conditioning system. The air flow needed
is 1000 CFM. Looking at the cooling speed
chart for *MV90704BXA, find the air flow closest
to 1000 CFM. A cooling airflow of 990 CFM
can be attained by setting the cooling speed to
“C” and the adjustment to “-” (minus).
NOTE:
Continuous Fan Speed will be 56% of
high stage cooling.
4. Locate the blower speed selection DIP switches on the
integrated control module. Select the desired “cooling” speed
tap by positioning switches 1 and 2 appropriately. Select the
desired “adjust” tap by positioning switches 3 and 4
appropriately. Refer to the following figure for switch positions
and their corresponding taps. Turn off power to furnace for a
minimum of 10 seconds, allowing motor to reset and
recognize new speed selection. Turn on power to furnace.
Verify CFM by counting the number of times the green CFM
LED blinks.
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.
Ramping Profiles
5
6
A*
OFF
OFF
B
ON
OFF
C
OFF
ON
D
ON
ON
DIP Switch No.
(* indicates factory setting)
•
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% CFM
100% CFM
82% 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% CFM
OFF
OFF
Cooling Demand
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 GMV95704BXA 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 GMV95704BXA.
This setting will keep electrical consumption to
a minimum. Set the “Heat” speed DIP switches
to “A”.
Heating Speed Tap
7
8
A
OFF
OFF
B*
ON
OFF
C
OFF
ON
D
ON
ON
DIP Switch No.
(* indicates factory setting)
*NOTE: Please contact your distributor or our website for the applicable product data book referred to in this manual.
Summary of Contents for GCV9 Series
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