Goodman ACS series Service Instructions Manual page 66

PRODUCT DESIGN
Fossil Fuel Applications
The 80% & 90% Single-Stage and Two-Stage furnaces can
be used in conjunction with a heat pump in a fossil fuel
application. A fossil fuel application is where an outdoor tem-
perature sensor determines the most cost efficient means
of heating (heat pump, gas furnace, or both).
A heat pump thermostat with two stages of heat is required
to properly use the single-stage furnace with a heat pump.
A heat pump thermostat with three stages of heat is re-
quired to properly use the two-stage furnace with a heat
pump. Refer to dual fuel, AFE-18-60A installation manual
(IO-627) for additional wiring instructions.
CONTINUOUS FAN OPERATION
SINGLE STAGE 80% AND 90% FURNACES
The single stage furnace control will energize the heating
circulator fan speed when the fan switch on the thermostat
is turned to the "ON" position.
TWO STAGE 80% & 90% VARIABLE SPEED
FURNACES
The two stage furnace control will energize ECM blower mo-
tor when the fan switch on the thermostat is turned to the
"ON" position. Continuous fan speed will be 56% of high
stage cooling. This fan speed will provide circulation with
less electricity than conventional single stage equipment.
CIRCULATOR BLOWER SPEED ADJUSTMENT
HIGH VOLTAGE
D ALL
ISCONNECT POWER BEFOR CHANGING SPEED TAPS.
M
ULTIPLE POWER SOURCES MAY BE PRESENT.
SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
66
WARNING
F
AILURE TO DO
All 80% & 90% single-stage and two-stage furnaces ship at
high speed for cooling and the speeds listed in the Specifi-
cation Sheet for heating. These speeds should be adjusted
by the installer to match the job requirements. See Specifi-
cation Sheet or Technical Manual for details.
Connect the correct motor leads to the COOL, HEAT, and
PARK terminals. If the heating speed equals cooling speed,
use the jumper wire provided. All unused motor leads that
are not connected to "PARK" terminals on the control must
be taped to prevent shorts.
All 80% & 90% Two-Stage Variable Speed furnaces are
shipped with heating speed set at "B" and cooling speed
set at "D". Use the following procedure to select the heating
and cooling speed needed for your unit.
Use the "GREEN" CFM LED, 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 manufactur-
ers 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 clean-
ers or other devices may require specific air flows, con-
sult installation instructions of those devices for require-
ments.
3. Knowing the furnace model, locate the high stage cool-
ing 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 adjust-
ment setting.
EXAMPLE: A *MV90704CXA furnace installed with a
2.5 ton air conditioning system. The air flow needed is
1000 CFM. Looking at the cooling speed chart for
*MV90704CXA, find the air flow closest to 1000 CFM. A
cooling airflow of 990 CFM may be attained by setting
the cooling speed to "C" and the adjustment to "-" (mi-
nus). NOTE: Continous 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
the motor to reset and recognize the new speed selec-
tion. Turn on power to furnace. Verify CFM by counting
the number of times the green CFM LED blinks.